System and method for initiating a forced migration of a virtual machine in a high-performance computing environment

ABSTRACT

Systems and methods for initiating a forced migration of a virtual machine. An exemplary embodiment can provide a subnet manager (SM) and an active virtual machine registration cache, where the subnet manager can access the active virtual machine registration cache. The SM can record a first virtual machine incarnation number in the active virtual machine registration cache, where the virtual machine incarnation number is associated with an active virtual machine (VM). Upon receiving a request to register the active VM on a different host, the SM can evaluate a second virtual machine incarnation number with the first virtual machine incarnation number to determine the legality of the request. In accordance with an embodiment, if the second virtual machine incarnation number is evaluated as greater than the first virtual machine incarnation number, the SM determines the request is legal.

CLAIM OF PRIORITY AND CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. Provisional Patent Application entitled “SYSTEM AND METHOD FOR PROVIDING USING ADMIN PARTITIONS TO CORRELATE RESOURCE ACCESS AND OWNERSHIP IN A HIGH PERFORMANCE COMPUTING ENVIRONMENT”, Application Ser. No. 62/287,712, filed on Jan. 27, 2016, which is hereby incorporated by reference in its entirety.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

This application is related to the following patent applications, each of which is hereby incorporated by reference in its entirety:

U.S. Patent Application entitled “SYSTEM AND METHOD FOR CORRELATING FABRIC-LEVEL GROUP MEMBERSHIP WITH SUBNET-LEVEL PARTITION MEMBERSHIP IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/415,620, filed Jan. 25, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD FOR SUPPORTING ON-DEMAND SETUP OF LOCAL HOST CHANNEL ADAPTER PORT PARTITION MEMBERSHIP IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/417,265, filed Jan. 27, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD OF ASSIGNING ADMIN PARTITION MEMBERSHIP BASED ON SWITCH CONNECTIVITY IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/415,644, filed Jan. 25, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD FOR DEFINING VIRTUAL MACHINE FABRIC PROFILES OF VIRTUAL MACHINES IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/415,668, filed Jan. 25, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD OF HOST-SIDE CONFIGURATION OF A HOST CHANNEL ADAPTER (HCA) IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/415,683, filed Jan. 25, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD OF INITIATING VIRTUAL MACHINE CONFIGURATION ON A SUBORDINATE NODE FROM A PRIVILEGED NODE IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/415,698, filed Jan. 25, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD FOR APPLICATION OF VIRTUAL HOST CHANNEL ADAPTER CONFIGURATION POLICIES IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/415,709, filed Jan. 25, 2017;

U.S. Patent Application entitled “SYSTEM AND METHOD FOR USING VIRTUAL MACHINE FABRIC PROFILES TO REDUCE VIRTUAL MACHINE DOWNTIME DURING MIGRATION IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/417,281, filed Jan. 27, 2017; and

U.S. Patent Application entitled “SYSTEM AND METHOD OF RESERVING A SPECIFIC QUEUE PAIR NUMBER FOR PROPRIETARY MANAGEMENT TRAFFIC IN A HIGH-PERFORMANCE COMPUTING ENVIRONMENT”, application Ser. No. 15/417,289, filed Jan. 27, 2017.

FIELD OF INVENTION

The present invention is generally related to computer systems, and is particularly related to virtual machine migration in a high performance network environment.

BACKGROUND

As larger cloud computing architectures are introduced, the performance and administrative bottlenecks associated with the traditional network and storage have become a significant problem. There has been an increased interest in using high performance lossless interconnects such as InfiniBand™ (IB) technology as the foundation for a cloud computing fabric. This is the general area that embodiments of the invention are intended to address.

SUMMARY

Described herein are systems and methods for initiating a forced migration of a virtual machine. An exemplary embodiment can provide a subnet manager (SM) and an active virtual machine registration cache, where the subnet manager can access the active virtual machine registration cache. The SM can record a first virtual machine incarnation number in the active virtual machine registration cache, where the virtual machine incarnation number is associated with an active virtual machine (VM). Upon receiving a request to register the active VM on a different host, the SM can evaluate a second virtual machine incarnation number with the first virtual machine incarnation number to determine the legality of the request. In accordance with an embodiment, if the second virtual machine incarnation number is evaluated as greater than the first virtual machine incarnation number, the SM determines the request is legal.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an illustration of an InfiniBand™ environment, in accordance with an embodiment.

FIG. 2 shows an illustration of a partitioned cluster environment, in accordance with an embodiment

FIG. 3 shows an illustration of a tree topology in a network environment, in accordance with an embodiment.

FIG. 4 shows an exemplary shared port architecture, in accordance with an embodiment.

FIG. 5 shows an exemplary vSwitch architecture, in accordance with an embodiment.

FIG. 6 shows an exemplary vPort architecture, in accordance with an embodiment.

FIG. 7 shows an exemplary vSwitch architecture with prepopulated LIDs, in accordance with an embodiment.

FIG. 8 shows an exemplary vSwitch architecture with dynamic LID assignment, in accordance with an embodiment.

FIG. 9 shows an exemplary vSwitch architecture with vSwitch with dynamic LID assignment and prepopulated LIDs, in accordance with an embodiment.

FIG. 10 shows an exemplary multi-subnet InfiniBand™ fabric, in accordance with an embodiment.

FIG. 11 shows an exemplary InfiniBand™ fabric and subnet including exemplary physical and logical subnet resources, in accordance with an embodiment.

FIG. 12 an exemplary InfiniBand™ fabric and subnet including exemplary subnet resources as members of different admin partitions, in accordance with an embodiment.

FIG. 13 shows an exemplary InfiniBand™ fabric and subnet including exemplary subnet resources as members of a hierarchical management scheme, including both admin partitions and resource domains, in accordance with an embodiment.

FIG. 14 is a flowchart for a method for assigning mutual access rights to members and associated resources of an admin partition associated with a fabric-level resource domain, in accordance with an embodiment.

FIG. 15 shows an exemplary database structure for storing VM fabric profile information, in accordance with an embodiment.

FIG. 16 is a flow chart for making a VM fabric profile available to subnet resources, in accordance with an embodiment.

FIG. 17 shows an exemplary host channel adapter including the control API, in accordance with an embodiment.

FIG. 18 shows an exemplary host channel adapter including configurable attributes, in accordance with an embodiment.

FIG. 19 shows subnet hosts with VM incarnation numbers as attributes of host channel adapters, in accordance with an embodiment.

FIG. 20 is a flow chart of a process of forced deregistration of a virtual host channel adapter from a virtual function.

FIG. 21 is a flow chart for initiating a forced migration of a virtual machine from one host to another.

DETAILED DESCRIPTION

The invention is illustrated, by way of example and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” or “some” embodiment(s) in this disclosure are not necessarily to the same embodiment, and such references mean at least one. While specific implementations are discussed, it is understood that the specific implementations are provided for illustrative purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without departing from the scope and spirit of the invention.

Common reference numerals can be used to indicate like elements throughout the drawings and detailed description; therefore, reference numerals used in a figure may or may not be referenced in the detailed description specific to such figure if the element is described elsewhere.

Described herein are systems and methods for initiating a forced migration of a virtual machine in a high performance network.

The following description of the invention uses an InfiniBand™ (IB) network as an example for a high performance network. Throughout the following description, reference can be made to the InfiniBand™ specification (also referred to variously as the InfiniBand specification, IB specification, or the legacy IB specification). Such reference is understood to refer to the InfiniBand® Trade Association Architecture Specification, Volume 1, Version 1.3, released March, 2015, available at http://www.inifinibandta.org, which is herein incorporated by reference in its entirety. It will be apparent to those skilled in the art that other types of high performance networks can be used without limitation. The following description also uses the fat-tree topology as an example for a fabric topology. It will be apparent to those skilled in the art that other types of fabric topologies can be used without limitation.

InfiniBand™

InfiniBand™ (IB) is an open standard lossless network technology developed by the InfiniBand™ Trade Association. The technology is based on a serial point-to-point full-duplex interconnect that offers high throughput and low latency communication, geared particularly towards high-performance computing (HPC) applications and datacenters.

The InfiniBand™ Architecture (IBA) supports a two-layer topological division. At the lower layer, IB networks are referred to as subnets, where a subnet can include a set of hosts interconnected using switches and point-to-point links. At the higher level, an IB fabric constitutes one or more subnets, which can be interconnected using routers.

Within a subnet, hosts can be connected using switches and point-to-point links. Additionally, there can be a master management entity, the subnet manager (SM), which resides on a designated device in the subnet. The subnet manager is responsible for configuring, activating and maintaining the IB subnet. Additionally, the subnet manager (SM) can be responsible for performing routing table calculations in an IB fabric. Here, for example, the routing of the IB network aims at proper load balancing between all source and destination pairs in the local subnet.

Through the subnet management interface, the subnet manager exchanges control packets, which are referred to as subnet management packets (SMPs), with subnet management agents (SMAs). The subnet management agents reside on every IB subnet device. By using SMPs, the subnet manager is able to discover the fabric, configure end-nodes and switches, and receive notifications from SMAs.

In accordance with an embodiment, intra-subnet routing in an IB network can be based on linear forwarding tables (LFTs) stored in the switches. The LFTs are calculated by the SM according to the routing mechanism in use. In a subnet, Host Channel Adapter (HCA) ports on the end nodes and switches are addressed using local identifiers (LIDs). Each entry in a linear forwarding table (LFT) consists of a destination LID (DLID) and an output port. Only one entry per LID in the table is supported. When a packet arrives at a switch, its output port is determined by looking up the DLID in the forwarding table of the switch. The routing is deterministic as packets take the same path in the network between a given source-destination pair (LID pair).

Generally, all other subnet managers, excepting the master subnet manager, act in standby mode for fault-tolerance. In a situation where a master subnet manager fails, however, a new master subnet manager is negotiated by the standby subnet managers. The master subnet manager also performs periodic sweeps of the subnet to detect any topology changes and reconfigures the network accordingly.

Furthermore, hosts and switches within a subnet can be addressed using local identifiers (LIDs), and a single subnet can be limited to 49151 unicast LIDs. Besides the LIDs, which are the local addresses that are valid within a subnet, each IB device can have a 64-bit global unique identifier (GUID). A GUID can be used to form a global identifier (GID), which is an IB layer three (L3) address.

The SM can calculate routing tables (i.e., the connections/routes between each pair of nodes within the subnet) at network initialization time. Furthermore, the routing tables can be updated whenever the topology changes, in order to ensure connectivity and optimal performance. During normal operations, the SM can perform periodic light sweeps of the network to check for topology changes. If a change is discovered during a light sweep or if a message (trap) signaling a network change is received by the SM, the SM can reconfigure the network according to the discovered changes.

For example, the SM can reconfigure the network when the network topology changes, such as when a link goes down, when a device is added, or when a link is removed. The reconfiguration steps can include the steps performed during the network initialization. Furthermore, the reconfigurations can have a local scope that is limited to the subnets in which the network changes occurred. Also, the segmenting of a large fabric with routers may limit the reconfiguration scope.

An example InfiniBand™ fabric is shown in FIG. 1, which shows an illustration of an InfiniBand™ environment 100, in accordance with an embodiment. In the example shown in FIG. 1, nodes A-E, 101-105, use the InfiniBand™ fabric 120 to communicate, via the respective host channel adapters 111-115. In accordance with an embodiment, the various nodes, e.g., nodes A-E 101-105, can be represented by various physical devices. In accordance with an embodiment, the various nodes, e.g., nodes A-E 101-105, can be represented by various virtual devices, such as virtual machines.

Data Partitions in InfiniBand™

In accordance with an embodiment, IB networks can support partitioning as a security mechanism to provide for isolation of logical groups of systems sharing a network fabric. Each HCA port on a node in the fabric can be a member of one or more partitions. In accordance with an embodiment, the present disclosure provides for two types of partitions that can be defined within an IB subnet—data partitions (discussed in detail in the following paragraphs) and admin partitions (discussed in detail later in the disclosure).

Data partition memberships are managed by a centralized partition manager, which can be part of the SM. The SM can configure data partition membership information on each port as a table of 16-bit partition keys (P_Keys). The SM can also configure switch and router ports with the data partition enforcement tables containing P_Key information associated with the end-nodes that send or receive data traffic through these ports. Additionally, in a general case, data partition membership of a switch port can represent a union of all membership indirectly associated with LI Ds routed via the port in an egress (towards the link) direction.

In accordance with an embodiment, data partitions are logical groups of ports such that the members of a group can only communicate to other members of the same logical group. At host channel adapters (HCAs) and switches, packets can be filtered using the data partition membership information to enforce isolation. Packets with invalid partitioning information can be dropped as soon as the packets reaches an incoming port. In partitioned IB systems, data partitions can be used to create tenant clusters. With data partition enforcement in place, a node cannot communicate with other nodes that belong to a different tenant cluster. In this way, the security of the system can be guaranteed even in the presence of compromised or malicious tenant nodes.

In accordance with an embodiment, for the communication between nodes, Queue Pairs (QPs) and End-to-End contexts (EECs) can be assigned to a particular data partition, except for the management Queue Pairs (QP0 and QP1). The P_Key information can then be added to every IB transport packet sent. When a packet arrives at an HCA port or a switch, its P_Key value can be validated against a table configured by the SM. If an invalid P_Key value is found, the packet is discarded immediately. In this way, communication is allowed only between ports sharing a data partition.

An example of IB data partitions is shown in FIG. 2, which shows an illustration of a data partitioned cluster environment, in accordance with an embodiment. In the example shown in FIG. 2, nodes A-E, 101-105, use the InfiniBand™ fabric, 120, to communicate, via the respective host channel adapters 111-115. The nodes A-E are arranged into data partitions, namely data partition 1, 130, data partition 2, 140, and data partition 3, 150. Data partition 1 comprises node A 101 and node D 104. Data partition 2 comprises node A 101, node B 102, and node C 103. Data partition 3 comprises node C 103 and node E 105. Because of the arrangement of the data partitions, node D 104 and node E 105 are not allowed to communicate as these nodes do not share a data partition. Meanwhile, for example, node A 101 and node C 103 are allowed to communicate as these nodes are both members of data partition 2, 140.

Virtual Machines in InfiniBand™

During the last decade, the prospect of virtualized High Performance Computing (HPC) environments has improved considerably as CPU overhead has been practically removed through hardware virtualization support; memory overhead has been significantly reduced by virtualizing the Memory Management Unit; storage overhead has been reduced by the use of fast SAN storages or distributed networked file systems; and network I/O overhead has been reduced by the use of device passthrough techniques like Single Root Input/Output Virtualization (SR-IOV). It is now possible for clouds to accommodate virtual HPC (vHPC) clusters using high performance interconnect solutions and deliver the necessary performance.

However, when coupled with lossless networks, such as InfiniBand™ (IB), certain cloud functionality, such as live migration of virtual machines (VMs), still remains an issue due to the complicated addressing and routing schemes used in these solutions. IB is an interconnection network technology offering high bandwidth and low latency, thus, is very well suited for HPC and other communication intensive workloads.

The traditional approach for connecting IB devices to VMs is by utilizing SR-IOV with direct assignment. However, achieving live migration of VMs assigned with IB Host Channel Adapters (HCAs) using SR-IOV has proved to be challenging. Each IB connected node has three different addresses: LID, GUID, and GID. When a live migration happens, one or more of these addresses change. Other nodes communicating with the VM-in-migration can lose connectivity. When this happens, the lost connection can be attempted to be renewed by locating the virtual machine's new address to reconnect to by sending Subnet Administration (SA) path record queries to the IB Subnet Manager (SM).

IB uses three different types of addresses. A first type of address is the 16 bits Local Identifier (LID). At least one unique LID is assigned to each HCA port and each switch by the SM. The LIDs are used to route traffic within a subnet. Since the LID is 16 bits long, 65536 unique address combinations can be made, of which only 49151 (0x0001-0xBFFF) can be used as unicast addresses. Consequently, the number of available unicast addresses defines the maximum size of an IB subnet. A second type of address is the 64 bits Global Unique Identifier (GUID) assigned by the manufacturer to each device (e.g. HCAs and switches) and each HCA port. The SM may assign additional subnet unique GUIDs to an HCA port, which is useful when SR-IOV is used. A third type of address is the 128 bits Global Identifier (GID). The GID is a valid IPv6 unicast address, and at least one is assigned to each HCA port. The GID is formed by combining a globally unique 64 bits prefix assigned by the fabric administrator, and the GUID address of each HCA port.

Fat-Tree (FTree) Topolodies and Routind

In accordance with an embodiment, some of the IB based HPC systems employ a fat-tree topology to take advantage of the useful properties fat-trees offer. These properties include full bisection-bandwidth and inherent fault-tolerance due to the availability of multiple paths between each source destination pair. The initial idea behind fat-trees was to employ fatter links between nodes, with more available bandwidth, as the tree moves towards the roots of the topology. The fatter links can help to avoid congestion in the upper-level switches and the bisection-bandwidth is maintained.

FIG. 3 shows an illustration of a tree topology in a network environment, in accordance with an embodiment. As shown in FIG. 3, one or more end-nodes 201-204 can be connected in a network fabric 200. The network fabric 200 can be based on a fat-tree topology, which includes a plurality of leaf switches 211-214, and multiple spine switches or root switches 231-234. Additionally, the network fabric 200 can include one or more intermediate switches, such as switches 221-224.

Also as shown in FIG. 3, each of the end-nodes 201-204 can be a multi-homed node, i.e., a single node that is connected to two or more parts of the network fabric 200 through multiple ports. For example, the node 201 can include the ports H1 and H2, the node 202 can include the ports H3 and H4, the node 203 can include the ports H5 and H6, and the node 204 can include the ports H7 and H8.

Additionally, each switch can have multiple switch ports. For example, the root switch 231 can have the switch ports 1-2, the root switch 232 can have the switch ports 3-4, the root switch 233 can have the switch ports 5-6, and the root switch 234 can have the switch ports 7-8.

In accordance with an embodiment, the fat-tree routing mechanism is one of the most popular routing algorithm for IB based fat-tree topologies. The fat-tree routing mechanism is also implemented in the OFED (Open Fabric Enterprise Distribution—a standard software stack for building and deploying IB based applications) subnet manager, OpenSM.

The fat-tree routing mechanism aims to generate LFTs that evenly spread shortest-path routes across the links in the network fabric. The mechanism traverses the fabric in the indexing order and assigns target LIDs of the end-nodes, and thus the corresponding routes, to each switch port. For the end-nodes connected to the same leaf switch, the indexing order can depend on the switch port to which the end-node is connected (i.e., port numbering sequence). For each port, the mechanism can maintain a port usage counter, and can use this port usage counter to select a least-used port each time a new route is added.

In accordance with an embodiment, in a partitioned subnet, nodes that are not members of a common data partition are not allowed to communicate. Practically, this means that some of the routes assigned by the fat-tree routing algorithm are not used for the user traffic. The problem arises when the fat tree routing mechanism generates LFTs for those routes the same way it does for the other functional paths. This behavior can result in degraded balancing on the links, as nodes are routed in the order of indexing. As routing can be performed oblivious to the data partitions, fat-tree routed subnets, in general, provide poor isolation among data partitions.

In accordance with an embodiment, a Fat-Tree is a hierarchical network topology that can scale with the available network resources. Moreover, Fat-Trees are easy to build using commodity switches placed on different levels of the hierarchy. Different variations of Fat-Trees are commonly available, including k-ary-n-trees, Extended Generalized Fat-Trees (XGFTs), Parallel Ports Generalized Fat-Trees (PGFTs) and Real Life Fat-Trees (RLFTs).

A k-ary-n-tree is an n level Fat-Tree with kn end-nodes and n·k^(n-1) switches, each with 2k ports. Each switch has an equal number of up and down connections in the tree. XGFT Fat-Tree extends k-ary-n-trees by allowing both different number of up and down connections for the switches, and different number of connections at each level in the tree. The PGFT definition further broadens the XGFT topologies and permits multiple connections between switches. A large variety of topologies can be defined using XGFTs and PGFTs. However, for practical purposes, RLFT, which is a restricted version of PGFT, is introduced to define Fat-Trees commonly found in today's HPC clusters. An RLFT uses the same port-count switches at all levels in the Fat-Tree.

Input/Output (I/O) Virtualization

In accordance with an embodiment, I/O Virtualization (IOV) can provide availability of I/O by allowing virtual machines (VMs) to access the underlying physical resources. The combination of storage traffic and inter-server communication impose an increased load that may overwhelm the I/O resources of a single server, leading to backlogs and idle processors as they are waiting for data. With the increase in number of I/O requests, IOV can provide availability; and can improve performance, scalability and flexibility of the (virtualized) I/O resources to match the level of performance seen in modern CPU virtualization.

In accordance with an embodiment, IOV is desired as it can allow sharing of I/O resources and provide protected access to the resources from the VMs. IOV decouples a logical device, which is exposed to a VM, from its physical implementation. Currently, there can be different types of IOV technologies, such as emulation, paravirtualization, direct assignment (DA), and single root-I/O virtualization (SR-IOV).

In accordance with an embodiment, one type of IOV technology is software emulation. Software emulation can allow for a decoupled front-end/back-end software architecture. The front-end can be a device driver placed in the VM, communicating with the back-end implemented by a hypervisor to provide I/O access. The physical device sharing ratio is high and live migrations of VMs are possible with just a few milliseconds of network downtime. However, software emulation introduces additional, undesired computational overhead.

In accordance with an embodiment, another type of IOV technology is direct device assignment. Direct device assignment involves a coupling of I/O devices to VMs, with no device sharing between VMs. Direct assignment, or device passthrough, provides near to native performance with minimum overhead. The physical device bypasses the hypervisor and is directly attached to the VM. However, a downside of such direct device assignment is limited scalability, as there is no sharing among virtual machines—one physical network card is coupled with one VM.

In accordance with an embodiment, Single Root IOV (SR-IOV) can allow a physical device to appear through hardware virtualization as multiple independent lightweight instances of the same device. These instances can be assigned to VMs as passthrough devices, and accessed as Virtual Functions (VFs). The hypervisor accesses the device through a unique (per device), fully featured Physical Function (PF). SR-IOV eases the scalability issue of pure direct assignment. However, a problem presented by SR-IOV is that it can impair VM migration. Among these IOV technologies, SR-IOV can extend the PCI Express (PCIe) specification with the means to allow direct access to a single physical device from multiple VMs while maintaining near to native performance. Thus, SR-IOV can provide good performance and scalability.

SR-IOV allows a PCIe device to expose multiple virtual devices that can be shared between multiple guests by allocating one virtual device to each guest. Each SR-IOV device has at least one physical function (PF) and one or more associated virtual functions (VF). A PF is a normal PCIe function controlled by the virtual machine monitor (VMM), or hypervisor, whereas a VF is a light-weight PCIe function. Each VF has its own base address (BAR) and is assigned with a unique requester ID that enables I/O memory management unit (IOMMU) to differentiate between the traffic streams to/from different VFs. The IOMMU also apply memory and interrupt translations between the PF and the VFs.

Unfortunately, however, direct device assignment techniques pose a barrier for cloud providers in situations where transparent live migration of virtual machines is desired for data center optimization. The essence of live migration is that the memory contents of a VM are copied to a remote hypervisor. Then the VM is paused at the source hypervisor, and the VM's operation is resumed at the destination. When using software emulation methods, the network interfaces are virtual so their internal states are stored into the memory and get copied as well. Thus the downtime could be brought down to a few milliseconds.

However, migration becomes more difficult when direct device assignment techniques, such as SR-IOV, are used. In such situations, a complete internal state of the network interface cannot be copied as it is tied to the hardware. The SR-IOV VFs assigned to a VM are instead detached, the live migration will run, and a new VF will be attached at the destination. In the case of InfiniBand™ and SR-IOV, this process can introduce downtime in the order of seconds. Moreover, in an SR-IOV shared port model the addresses of the VM will change after the migration, causing additional overhead in the SM and a negative impact on the performance of the underlying network fabric.

InfiniBand™ SR-IOV Architecture—Shared Port

There can be different types of SR-IOV models, e.g. a shared port model, a virtual switch model, and a virtual port model.

FIG. 4 shows an exemplary shared port architecture, in accordance with an embodiment. As depicted in the figure, a host 300 (e.g., a host channel adapter) can interact with a hypervisor 310, which can assign the various virtual functions 330, 340, 350, to a number of virtual machines. As well, the physical function can be handled by the hypervisor 310.

In accordance with an embodiment, when using a shared port architecture, such as that depicted in FIG. 4, the host, e.g., HCA, appears as a single port in the network with a single shared LID and shared Queue Pair (QP) space between the physical function 320 and the virtual functions 330, 350, 350. However, each function (i.e., physical function and virtual functions) can have their own GID.

As shown in FIG. 4, in accordance with an embodiment, different GIDs can be assigned to the virtual functions and the physical function, and the special queue pairs, QPO and QP1 (i.e., special purpose queue pairs that are used for InfiniBand™ management packets), are owned by the physical function. These QPs are exposed to the VFs as well, but the VFs are not allowed to use QPO (all SMPs coming from VFs towards QPO are discarded), and QP1 can act as a proxy of the actual QP1 owned by the PF.

In accordance with an embodiment, the shared port architecture can allow for highly scalable data centers that are not limited by the number of VMs (which attach to the network by being assigned to the virtual functions), as the LID space is only consumed by physical machines and switches in the network.

However, a shortcoming of the shared port architecture is the inability to provide transparent live migration, hindering the potential for flexible VM placement. As each LID is associated with a specific hypervisor, and shared among all VMs residing on the hypervisor, a migrating VM (i.e., a virtual machine migrating to a destination hypervisor) has to have its LID changed to the LID of the destination hypervisor. Furthermore, as a consequence of the restricted QPO access, a subnet manager cannot run inside a VM.

InfiniBand™ SR-IOV Architecture Models—Virtual Switch (vSwitch)

FIG. 5 shows an exemplary vSwitch architecture, in accordance with an embodiment. As depicted in the figure, a host 400 (e.g., a host channel adapter) can interact with a hypervisor 410, which can assign the various virtual functions 430, 440, 450, to a number of virtual machines. As well, the physical function can be handled by the hypervisor 410. A virtual switch 415 can also be handled by the hypervisor 401.

In accordance with an embodiment, in a vSwitch architecture each virtual function 430, 440, 450 is a complete virtual Host Channel Adapter (vHCA), meaning that the VM assigned to a VF is assigned a complete set of IB addresses (e.g., GID, GUID, LID) and a dedicated QP space in the hardware. For the rest of the network and the SM, the HCA 400 looks like a switch, via the virtual switch 415, with additional nodes connected to it. The hypervisor 410 can use the PF 420, and the VMs (attached to the virtual functions) use the VFs.

In accordance with an embodiment, a vSwitch architecture provide transparent virtualization. However, because each virtual function is assigned a unique LID, the number of available LIDs gets consumed rapidly. As well, with many LID addresses in use (i.e., one each for each physical function and each virtual function), more communication paths have to be computed by the SM and more Subnet Management Packets (SMPs) have to be sent to the switches in order to update their LFTs. For example, the computation of the communication paths might take several minutes in large networks. Because LID space is limited to 49151 unicast LIDs, and as each VM (via a VF), physical node, and switch occupies one LID each, the number of physical nodes and switches in the network limits the number of active VMs, and vice versa.

InfiniBand™ SR-IOV Architecture Models—Virtual Port (vPort)

FIG. 6 shows an exemplary vPort concept, in accordance with an embodiment. As depicted in the figure, a host 300 (e.g., a host channel adapter) can interact with a hypervisor 410, which can assign the various virtual functions 330, 340, 350, to a number of virtual machines. As well, the physical function can be handled by the hypervisor 310.

In accordance with an embodiment, the vPort concept is loosely defined in order to give freedom of implementation to vendors (e.g. the definition does not rule that the implementation has to be SR-IOV specific), and a goal of the vPort is to standardize the way VMs are handled in subnets. With the vPort concept, both SR-IOV Shared-Port-like and vSwitch-like architectures or a combination of both, that can be more scalable in both the space and performance domains, can be defined. A vPort supports optional LIDs, and unlike the Shared-Port, the SM is aware of all the vPorts available in a subnet even if a vPort is not using a dedicated LID.

InfiniBand™ SR-IOV Architecture Models—vSwitch with Prepopulated LIDs

In accordance with an embodiment, the present disclosure provides a system and method for providing a vSwitch architecture with prepopulated LIDs.

FIG. 7 shows an exemplary vSwitch architecture with prepopulated LIDs, in accordance with an embodiment. As depicted in the figure, a number of switches 501-504 can provide communication within the network switched environment 600 (e.g., an IB subnet) between members of a fabric, such as an InfiniBand™ fabric. The fabric can include a number of hardware devices, such as host channel adapters 510, 520, 530. Each of the host channel adapters 510, 520, 530, can in turn interact with a hypervisor 511, 521, and 531, respectively. Each hypervisor can, in turn, in conjunction with the host channel adapter it interacts with, setup and assign a number of virtual functions 514, 515, 516, 524, 525, 526, 534, 535, 536, to a number of virtual machines. For example, virtual machine 1 550 can be assigned by the hypervisor 511 to virtual function 1 514. Hypervisor 511 can additionally assign virtual machine 2 551 to virtual function 2 515, and virtual machine 3 552 to virtual function 3 516. Hypervisor 531 can, in turn, assign virtual machine 4 553 to virtual function 1 534. The hypervisors can access the host channel adapters through a fully featured physical function 513, 523, 533, on each of the host channel adapters.

In accordance with an embodiment, each of the switches 501-504 can comprise a number of ports (not shown), which are used in setting a linear forwarding table (LFT) in order to direct traffic within the network switched environment 600.

In accordance with an embodiment, the virtual switches 512, 522, and 532, can be handled by their respective hypervisors 511, 521, 531. In such a vSwitch architecture each virtual function is a complete virtual Host Channel Adapter (vHCA), meaning that the VM assigned to a VF is assigned a complete set of IB addresses (e.g., GID, GUID, LID) and a dedicated QP space in the hardware. For the rest of the network and the SM (not shown), the HCAs 510, 520, and 530 look like a switch, via the virtual switches, with additional nodes connected to them.

In accordance with an embodiment, the present disclosure provides a system and method for providing a vSwitch architecture with prepopulated LIDs. Referring to FIG. 7, the LIDs are prepopulated to the various physical functions 513, 523, 533, as well as the virtual functions 514-516, 524-526, 534-536 (even those virtual functions not currently associated with an active virtual machine). For example, physical function 513 is prepopulated with LID 1, while virtual function 1 534 is prepopulated with LID 10. The LIDs are prepopulated in an SR-IOV vSwitch-enabled subnet when the network is booted. Even when not all of the VFs are occupied by VMs in the network, the populated VFs are assigned with a LID as shown in FIG. 7.

In accordance with an embodiment, much like physical host channel adapters can have more than one port (two ports are common for redundancy), virtual HCAs can also be represented with two ports and be connected via one, two or more virtual switches to the external IB subnet.

In accordance with an embodiment, in a vSwitch architecture with prepopulated LIDs, each hypervisor can consume one LID for itself through the PF and one more LID for each additional VF. The sum of all the VFs available in all hypervisors in an IB subnet, gives the maximum amount of VMs that are allowed to run in the subnet. For example, in an IB subnet with 16 virtual functions per hypervisor in the subnet, then each hypervisor consumes 17 LIDs (one LID for each of the 16 virtual functions plus one LID for the physical function) in the subnet. In such an IB subnet, the theoretical hypervisor limit for a single subnet is ruled by the number of available unicast LIDs and is: 2891 (49151 available LIDs divided by 17 LIDs per hypervisor), and the total number of VMs (i.e., the limit) is 46256 (2891 hypervisors times 16 VFs per hypervisor). (In actuality, these numbers are smaller since each switch, router, or dedicated SM node in the IB subnet consumes a LID as well). Note that the vSwitch does not need to occupy an additional LID as it can share the LID with the PF.

In accordance with an embodiment, in a vSwitch architecture with prepopulated LIDs, communication paths are computed for all the LIDs the first time the network is booted. When a new VM needs to be started the system does not have to add a new LID in the subnet, an action that would otherwise cause a complete reconfiguration of the network, including path recalculation, which is the most time consuming part. Instead, an available port for a VM is located (i.e., an available virtual function) in one of the hypervisors and the virtual machine is attached to the available virtual function.

In accordance with an embodiment, a vSwitch architecture with prepopulated LI Ds also allows for the ability to calculate and use different paths to reach different VMs hosted by the same hypervisor. Essentially, this allows for such subnets and networks to use a LID Mask Control (LMC) like feature to provide alternative paths towards one physical machine, without being bound by the limitation of the LMC that requires the LIDs to be sequential. The freedom to use non-sequential LIDs is particularly useful when a VM needs to be migrated and carry its associated LID to the destination.

In accordance with an embodiment, along with the benefits shown above of a vSwitch architecture with prepopulated LIDs, certain considerations can be taken into account. For example, because the LIDs are prepopulated in an SR-IOV vSwitch-enabled subnet when the network is booted, the initial path computation (e.g., on boot-up) can take longer than if the LI Ds were not pre-populated.

InfiniBand™ SR-IOV Architecture Models—vSwitch with Dynamic LID Assignment

In accordance with an embodiment, the present disclosure provides a system and method for providing a vSwitch architecture with dynamic LID assignment.

FIG. 8 shows an exemplary vSwitch architecture with dynamic LID assignment, in accordance with an embodiment. As depicted in the figure, a number of switches 501-504 can provide communication within the network switched environment 700 (e.g., an IB subnet) between members of a fabric, such as an InfiniBand™ fabric. The fabric can include a number of hardware devices, such as host channel adapters 510, 520, 530. Each of the host channel adapters 510, 520, 530, can in turn interact with a hypervisor 511, 521, 531, respectively. Each hypervisor can, in turn, in conjunction with the host channel adapter it interacts with, setup and assign a number of virtual functions 514, 515, 516, 524, 525, 526, 534, 535, 536, to a number of virtual machines. For example, virtual machine 1 550 can be assigned by the hypervisor 511 to virtual function 1 514. Hypervisor 511 can additionally assign virtual machine 2 551 to virtual function 2 515, and virtual machine 3 552 to virtual function 3 516. Hypervisor 531 can, in turn, assign virtual machine 4 553 to virtual function 1 534. The hypervisors can access the host channel adapters through a fully featured physical function 513, 523, 533, on each of the host channel adapters.

In accordance with an embodiment, each of the switches 501-504 can comprise a number of ports (not shown), which are used in setting a linear forwarding table in order to direct traffic within the network switched environment 700.

In accordance with an embodiment, the virtual switches 512, 522, and 532, can be handled by their respective hypervisors 511, 521, 531. In such a vSwitch architecture each virtual function is a complete virtual Host Channel Adapter (vHCA), meaning that the VM assigned to a VF is assigned a complete set of IB addresses (e.g., GID, GUID, LID) and a dedicated QP space in the hardware. For the rest of the network and the SM (not shown), the HCAs 510, 520, and 530 look like a switch, via the virtual switches, with additional nodes connected to them.

In accordance with an embodiment, the present disclosure provides a system and method for providing a vSwitch architecture with dynamic LID assignment. Referring to FIG. 8, the LI Ds are dynamically assigned to the various physical functions 513, 523, 533, with physical function 513 receiving LID 1, physical function 523 receiving LID 2, and physical function 533 receiving LID 3. Those virtual functions that are associated with an active virtual machine can also receive a dynamically assigned LID. For example, because virtual machine 1 550 is active and associated with virtual function 1 514, virtual function 514 can be assigned LID 5. Likewise, virtual function 2 515, virtual function 3 516, and virtual function 1 534 are each associated with an active virtual function. Because of this, these virtual functions are assigned LIDs, with LID 7 being assigned to virtual function 2 515, LID 11 being assigned to virtual function 3 516, and LID 9 being assigned to virtual function 1 534. Unlike vSwitch with prepopulated LIDs, those virtual functions not currently associated with an active virtual machine do not receive a LID assignment.

In accordance with an embodiment, with the dynamic LID assignment, the initial path computation can be substantially reduced. When the network is booting for the first time and no VMs are present then a relatively small number of LIDs can be used for the initial path calculation and LFT distribution.

In accordance with an embodiment, much like physical host channel adapters can have more than one port (two ports are common for redundancy), virtual HCAs can also be represented with two ports and be connected via one, two or more virtual switches to the external IB subnet.

In accordance with an embodiment, when a new VM is created in a system utilizing vSwitch with dynamic LID assignment, a free VM slot is found in order to decide on which hypervisor to boot the newly added VM, and a unique non-used unicast LID is found as well. However, there are no known paths in the network and the LFTs of the switches for handling the newly added LID. Computing a new set of paths in order to handle the newly added VM is not desirable in a dynamic environment where several VMs may be booted every minute. In large IB subnets, computing a new set of routes can take several minutes, and this procedure would have to repeat each time a new VM is booted.

Advantageously, in accordance with an embodiment, because all the VFs in a hypervisor share the same uplink with the PF, there is no need to compute a new set of routes. It is only needed to iterate through the LFTs of all the physical switches in the network, copy the forwarding port from the LID entry that belongs to the PF of the hypervisor—where the VM is created—to the newly added LID, and send a single SMP to update the corresponding LFT block of the particular switch. Thus the system and method avoids the need to compute a new set of routes.

In accordance with an embodiment, the LI Ds assigned in the vSwitch with dynamic LID assignment architecture do not have to be sequential. When comparing the LIDs assigned on VMs on each hypervisor in vSwitch with prepopulated LIDs versus vSwitch with dynamic LID assignment, it is notable that the LI Ds assigned in the dynamic LID assignment architecture are non-sequential, while those prepopulated are sequential in nature. In the vSwitch dynamic LID assignment architecture, when a new VM is created, the next available LID is used throughout the lifetime of the VM. Conversely, in a vSwitch with prepopulated LIDs, each VM inherits the LID that is already assigned to the corresponding VF, and in a network without live migrations, VMs consecutively attached to a given VF get the same LID.

In accordance with an embodiment, the vSwitch with dynamic LID assignment architecture can resolve the drawbacks of the vSwitch with prepopulated LIDs architecture model at a cost of some additional network and runtime SM overhead. Each time a VM is created, the LFTs of the physical switches in the subnet are updated with the newly added LID associated with the created VM. One subnet management packet (SMP) per switch is needed to be sent for this operation. The LMC-like functionality is also not available, because each VM is using the same path as its host hypervisor. However, there is no limitation on the total amount of VFs present in all hypervisors, and the number of VFs may exceed that of the unicast LID limit. Of course, not all of the VFs are allowed to be attached on active VMs simultaneously if this is the case, but having more spare hypervisors and VFs adds flexibility for disaster recovery and optimization of fragmented networks when operating close to the unicast LID limit.

InfiniBand™ SR-IOV Architecture Models—vSwitch with Dynamic LID Assionment and Prepopulated LIDs

FIG. 9 shows an exemplary vSwitch architecture with vSwitch with dynamic LID assignment and prepopulated LIDs, in accordance with an embodiment. As depicted in the figure, a number of switches 501-504 can provide communication within the network switched environment 800 (e.g., an IB subnet) between members of a fabric, such as an InfiniBand™ fabric. The fabric can include a number of hardware devices, such as host channel adapters 510, 520, 530. Each of the host channel adapters 510, 520, 530, can in turn interact with a hypervisor 511, 521, and 531, respectively. Each hypervisor can, in turn, in conjunction with the host channel adapter it interacts with, setup and assign a number of virtual functions 514, 515, 516, 524, 525, 526, 534, 535, 536, to a number of virtual machines. For example, virtual machine 1 550 can be assigned by the hypervisor 511 to virtual function 1 514. Hypervisor 511 can additionally assign virtual machine 2 551 to virtual function 2 515. Hypervisor 521 can assign virtual machine 3 552 to virtual function 3 526. Hypervisor 531 can, in turn, assign virtual machine 4 553 to virtual function 2 535. The hypervisors can access the host channel adapters through a fully featured physical function 513, 523, 533, on each of the host channel adapters.

In accordance with an embodiment, each of the switches 501-504 can comprise a number of ports (not shown), which are used in setting a linear forwarding table in order to direct traffic within the network switched environment 800.

In accordance with an embodiment, the virtual switches 512, 522, and 532, can be handled by their respective hypervisors 511, 521, 531. In such a vSwitch architecture each virtual function is a complete virtual Host Channel Adapter (vHCA), meaning that the VM assigned to a VF is assigned a complete set of IB addresses (e.g., GID, GUID, LID) and a dedicated QP space in the hardware. For the rest of the network and the SM (not shown), the HCAs 510, 520, and 530 look like a switch, via the virtual switches, with additional nodes connected to them.

In accordance with an embodiment, the present disclosure provides a system and method for providing a hybrid vSwitch architecture with dynamic LID assignment and prepopulated LIDs. Referring to FIG. 9, hypervisor 511 can be arranged with vSwitch with prepopulated LIDs architecture, while hypervisor 521 can be arranged with vSwitch with prepopulated LIDs and dynamic LID assignment. Hypervisor 531 can be arranged with vSwitch with dynamic LID assignment. Thus, the physical function 513 and virtual functions 514-516 have their LIDs prepopulated (i.e., even those virtual functions not attached to an active virtual machine are assigned a LID). Physical function 523 and virtual function 1 524 can have their LIDs prepopulated, while virtual function 2 and 3, 525 and 526, have their LIDs dynamically assigned (i.e., virtual function 2 525 is available for dynamic LID assignment, and virtual function 3 526 has a LID of 11 dynamically assigned as virtual machine 3 552 is attached). Finally, the functions (physical function and virtual functions) associated with hypervisor 3 531 can have their LIDs dynamically assigned. This results in virtual functions 1 and 3, 534 and 536, are available for dynamic LID assignment, while virtual function 2 535 has LID of 9 dynamically assigned as virtual machine 4 553 is attached there.

In accordance with an embodiment, such as that depicted in FIG. 9, where both vSwitch with prepopulated LIDs and vSwitch with dynamic LID assignment are utilized (independently or in combination within any given hypervisor), the number of prepopulated LI Ds per host channel adapter can be defined by a fabric administrator and can be in the range of 0 <=prepopulated VFs<=Total VFs (per host channel adapter), and the VFs available for dynamic LID assignment can be found by subtracting the number of prepopulated VFs from the total number of VFs (per host channel adapter).

In accordance with an embodiment, much like physical host channel adapters can have more than one port (two ports are common for redundancy), virtual HCAs can also be represented with two ports and be connected via one, two or more virtual switches to the external IB subnet.

InfiniBand™—Inter-Subnet Communication

In accordance with an embodiment, in addition to providing an InfiniBand™ fabric within a single subnet, embodiments of the current disclosure can also provide for an InfiniBand™ fabric that spans two or more subnets.

FIG. 10 shows an exemplary multi-subnet InfiniBand™ fabric, in accordance with an embodiment. As depicted in the figure, within subnet A 1000, a number of switches 1001-1004 can provide communication within subnet A 1000 (e.g., an IB subnet) between members of a fabric, such as an InfiniBand™ fabric. The fabric can include a number of hardware devices, such as, for example, channel adapter 1010. Host channel adapters 1010 can in turn interact with a hypervisor 1011. The hypervisor can, in turn, in conjunction with the host channel adapter it interacts with, setup a number of virtual functions 1014. The hypervisor can additionally assign virtual machines to each of the virtual functions, such as virtual machine 1 1015 being assigned to virtual function 1 1014. The hypervisor can access their associated host channel adapters through a fully featured physical function, such as physical function 1013, on each of the host channel adapters.

With further reference to FIG. 10, and in accordance with an embodiment, a number of switches 1021-1024 can provide communication within subnet B 1040 (e.g., an IB subnet) between members of a fabric, such as an InfiniBand™ fabric. The fabric can include a number of hardware devices, such as, for example, host channel adapter 1030. Host channel adapter 1030 can in turn interact with a hypervisor 1031. The hypervisor can, in turn, in conjunction with the host channel adapter it interacts with, setup a number of virtual functions 1034. The hypervisors can additionally assign virtual machines to each of the virtual functions, such as virtual machine 2 1035 being assigned to virtual function 2 1034. The hypervisor can access their associated host channel adapters through a fully featured physical function, such as physical function 1033, on each of the host channel adapters. It is noted that, although only one host channel adapter is shown within each subnet (i.e., subnet A and subnet B), it is to be understood that a plurality of host channel adapters, and their corresponding components, can be included within each subnet.

In accordance with an embodiment, each of the host channel adapters can additionally be associated with a virtual switch, such as virtual switch 1012 and virtual switch 1032, and each HCA can be set up with a different architecture model, as discussed above. Although both subnets within FIG. 10 are shown as using a vSwitch with prepopulated LID architecture model, this is not meant to imply that all such subnet configurations must follow a similar architecture model.

In accordance with an embodiment, at least one switch within each subnet can be associated with a router, such as switch 1002 within subnet A 1000 being associated with router 1005, and switch 1021 within subnet B 1040 being associated with router 1006.

In accordance with an embodiment, when traffic at an originating source, such as virtual machine 1 within subnet A, is addressed to a destination at a different subnet, such as virtual machine 2 within subnet B, the traffic can be addressed to the router within subnet A, i.e., router 1005, which can then pass the traffic to subnet B via its link with router 1006.

Fabric Manager

As discussed above, a network fabric, such as an InfiniBand™ fabric, can span a plurality of subnets through the use of interconnected routers in each subnet of the fabric. In accordance with an embodiment, a fabric manager (not shown) can be implemented on a host which is a member of the network fabric and can be employed within the fabric to manage both physical and logical resources that are part of the fabric. For instance, management tasks such as discovering fabric resources, controlling connectivity between physical servers, collecting and viewing real-time network statistics, disaster recovery, and setting quality of service (QoS) settings, among others, may be performed by a user through the fabric manager. In accordance with an embodiment, the fabric manager may span all subnets defined in the fabric. That is, the fabric manager can manage physical and logical resources that are members of, or associated with, the fabric at large, regardless of which subnet the resources are a member of.

In accordance with an embodiment, the fabric manager can include a graphical user interface (GUI) through which a user can perform administration functions. The fabric manager GUI can incorporate visualization tools that allow a user to monitor and control fabric resources. For example, in an embodiment, a user can view server connections, configuration settings and performance statistics for servers across the fabric through the fabric interface. Other examples of fabric functionality that can be monitored and/or managed through the fabric manger GUI include discovering inter-subnet fabric topology, viewing visual representations of these topologies, creating fabric profiles (e.g., virtual machine fabric profiles), and building and management of a fabric manager database that can store fabric profiles, metadata, configuration settings and other data required by, and related to, the network fabric. In accordance with an embodiment, the fabric manager database is a fabric-level database.

In addition, the fabric manager can define legal inter-subnet connectivity in terms of which subnets are allowed to communicate via which router ports using which partition numbers. In accordance with an embodiment, the fabric manager is a centralized fabric management utility. The above examples are not meant to be limiting.

In accordance with an embodiment, some of the fabric manager's functionality can be initiated by a user, and other functionality can be abstracted from the user, or be automated (e.g., some functionality may be performed by the fabric manager upon startup, or at other predetermined events).

In an exemplary embodiment of a management event, a user may initiate, at the fabric manger interface, a configuration change directed towards a network fabric device. After receiving the configuration change request, the fabric manager may, in turn, ensure that the configuration change request is properly carried out. For example, the fabric manager may communicate the request to the device and ensure that the configuration change is written to the device's configuration. In one embodiment, the physical device acknowledges to the fabric manager that the configuration change has successfully completed. In accordance with an embodiment, the fabric manager may then update the interface to give a visual confirmation that the request has been carried out. Further, the fabric manager may persist the configuration of the device to the fabric manager database, e.g., for disaster recovery or other purposes.

In accordance with an embodiment, the fabric manager can have other interfaces, such as a command line interface, that includes some, all, or more functionality than the GUI.

Fabric-Level Resource Domains

As discussed above, a fabric manager can allow users to perform administrative tasks throughout the network fabric through an interface of the fabric manager. In accordance with an embodiment, an additional function of the fabric manager is facilitation of hierarchical role-based access control. In an embodiment, role-based access control is achieved through fabric-level resource domains.

In accordance with an embodiment, role-based access control is based on the concept of fabric users. Access from both human administrators and external management applications can represent an authenticated context that defines legal operations on all or a subset of the fabric infrastructure or fabric resources. For example, a user can be represented in the fabric by a user profile. That is, within the fabric a user can be defined by creating a profile of the user and assigning attributes to the profile. A user profile can be assigned a username attribute, and a password attribute, where the username is unique within the fabric, thereby uniquely identifying the user. Further, the user profile may be associated with certain roles defined in the fabric that assign certain access levels to different resources within the fabric. In accordance with an embodiment, setting up user profiles can be accomplished through the fabric manager interface. All or part of the user profile can be stored in the fabric manger database. Moreover, in an embodiment, the fabric manager can integrate with well-known user directories, such as Microsoft's® Active Directory or LDAP directories, or with, e.g., the RADIUS networking protocol for remote authentication.

In accordance with an embodiment, the fabric manager can manage fabric resources that it discovers through fabric-level resource domains (also referred to as “resource domains”, or simply “domains” herein). A resource domain is a logical grouping of fabric resources defined at the fabric level. Fabric resources include both physical and logical resources. Some examples of resources include fabric devices (such as HCAs, physical nodes, and switches), fabric profiles (such as virtual machine fabric profiles, and user profiles), virtual machines, clouds, and I/O modules, among others.

In accordance with an embodiment, all fabric resources discovered and managed by the fabric manager reside in the default domain, which exists by default (i.e., without the need to setup or configure it) in the fabric, and can be accessed through the fabric manager interface. The default domain is the highest level domain—that is, it is the parent domain to all other resource domains, and all other resource domains exist within the default domain. The default domain is associated with a fabric-level administrator, which also exists by default, and is configured with administrative privileges in the default domain by default.

In accordance with an embodiment, resource domains represent a hierarchical form of resource management. For example, the process of configuring and managing the default domain is available only to the fabric-level administrator. However, child domains can be created within the default domain by the fabric-level administrator. For instance, the fabric-level administrator can create a child domain and can add domain resources to the child domain. Additionally the fabric-level administrator can create domain-level “domain admin” users and add (i.e., associate) the domain admin users to the child domain. Making the domain admin user a member of the resource domain allows the domain admin user to manage the child domain and its contained subset of the fabric resources. In accordance with an embodiment, the domain admin user cannot manage resources outside of the child domain (i.e., resources at a parallel or a higher level than the domain admin is associated with). However the domain admin can manage resources contained in resource domains that have been created as child domains of the resource domain. In accordance with an embodiment, the fabric manager is responsible for providing the security that ensures that resource domain boundaries are strictly enforced.

FIG. 11 shows the hierarchical structure of resource domains. As shown, default domain 1102 exists within network fabric 1100. Fabric-level administrator 1110 has access rights to manage fabric-level resources 1112, 1124, and 1134. Fabric-level administrator 1110 can also create and administer new resource domains within default domain 1102. Fabric-level administrator 1110 has created resource domain 1120 and 1130, and corresponding domain-level domain admin users 1122 and 1132. Domain admin user 1122 has access rights to manage fabric resources 1124 (assigned to resource domain 1120 by fabric-level administrator 1110), but has no access rights to manage fabric resources 1112 (at a higher level) or domain resources 1134 (at a parallel level). Likewise, Domain admin user 1132 has access rights to manage fabric resources 1134 (assigned to resource domain 1130 by Fabric-level administrator 1110), but has no access rights to manage fabric resources 1112 (at a higher level) or domain resources 1124 (at a parallel level).

Admin Partitions

In accordance with an embodiment, a resource domain can be represented at the subnet level by an administration, or “admin” partition (as they are referred to herein). An admin partition represents a group membership which grants access rights at the subnet level to subnet resources. Members of an admin partition are considered privileged, in that the members have access rights to any subnet resources that are associated with the admin partition, in accordance with an embodiment. At the fabric manager level, an admin partition is associated with a resource domain and a corresponding domain admin user. Thus, user-role separation can be ensured in multi-tenant environments at the subnet level. Further, resource domain membership can be correlated with admin partition membership, so that resources that are members of an admin partition that is associated with a particular resource domain are also members of the resource domain.

In accordance with an embodiment, an admin partition can be defined at the subnet level in the same way that a data partition is defined, but with an additional attribute specifying that the partition being created is an admin partition. Like data partitions (discussed in detail, above), admin partitions can be created by an administrator through the fabric manager interface, in accordance with an embodiment. In an embodiment, the fabric manager can support an “admin partition” flag as an optional parameter during the creation of a partition. If selected by the creating administrator, the fabric manager will include the additional attribute specifying that the newly created partition is an admin partition, and will be treated as an admin partition by the fabric manager and the local master subnet manager.

In accordance with an embodiment, the fabric manager can be configured to automatically create a corresponding admin partition for each resource domain that is created, and associate the automatically created partition with the corresponding resource domain. In such an embodiment, when fabric-level resources are added to the resource domain, the fabric manager also associates them with the admin partition that was automatically created and associated with the resource domain. Thus, resources added to the resource domain will have subnet-level access rights to each other upon being added to the resource domain, with no further action being taken by the administrator (e.g., the fabric-level administrator or the domain admin).

Moreover, in accordance with an embodiment, entire subnets of the network can represent a special resource domain in a domain hierarchy that has a top-level domain (e.g., the default domain). For instance, in a domain hierarchy, where the default domain represents the top-level domain, each subnet of the network fabric can then be recognized by the fabric manager as a child domain of the default domain. Recognition of entire subnets as child domains of a top-level domain can be configured as default behavior of the fabric manager, or these default domains can be manually defined by an administrator. Here again, in order to have user role separation and enforcement of domain boundaries and resource associations at the subnet level, admin partitions corresponding to entire-subnet resource domains can be defined. In accordance with an embodiment, an admin partitions that is defined in a subnet and includes each resource in that subnet (as either a member, or associated with the admin partition) can be termed a “domain global” admin partition, since in this configuration, every resource in the subnet would have access rights to every other resource.

In accordance with an embodiment, an admin partition can be transparent to a domain admin. As noted above, a domain global admin partition can be created automatically for a resource domain at the fabric manager level, and then all resources assigned to or created within the scope of this domain can automatically be associated with the corresponding admin partition. In another embodiment, however, the domain admin can explicitly create different admin partitions within the relevant resource domain, and then resources within the domain can be explicitly associated with the explicitly created admin partition instead of with the admin partition that was created by default for the resource domain.

In accordance with an embodiment, the fabric manager can support the creation of both shared and private admin partitions. Admin partitions created by a fabric-level administrator in the default domain can be shared partitions that can be made available to individual resource domains. Admin partitions created by a domain admin (i.e., a user with credentials associated with a specific resource domain) in the domain in which the domain admin is a member can be private partitions associated with and available only to the specific resource domain in whose context the admin partitions were created.

In accordance with an embodiment, end-ports of HCAs and vHCAs can be members of an admin partition, just as they can be members of a data partition. Admin partitions are differentiated from data partitions, however, in that admin partitions can be associated with other subnet resources, in accordance with an embodiment. For example, a data partition can be associated with an admin partition. Further, an admin partition can be associated with another admin partition, as a child or as a parent, thus making admin partitions a hierarchical concept and able to correspond with the hierarchy of the resource domains they are associated with, in accordance with an embodiment.

As a technical matter, end-ports of HCAs (and vHCAs) can be referred to as “members” of partitions, in traditional terminology, and other resources can be “associated with” admin partitions, in accordance with an embodiment. The technical differences in these two concepts are explained below. For convenience and readability, however, this document may occasionally, in reference to admin partitions, use the terms “member” and “associated with” interchangeably. Notwithstanding the use of these terms interchangeably, it is to be understood that the technical differences between end-port/HCA membership in, and resource association with, admin partitions is meant to be consistently applied by the reader.

In accordance with an embodiment, an admin partition is defined by a P_Key, just as a data partition is defined. However, while an end-port is aware of the data partitions that it is a member of, it is not necessary that end-ports be aware of what admin partitions they are members of. Thus, in one embodiment, a P_Key defining an admin partition is not entered in the P_Key table of member end-ports. In this way the creation of an admin partition does not waste P_Key table entries—which are a limited resource—if an admin partition is not used for IB packet traffic. In another embodiment, however, an admin partition may function as both an admin partition and a data partition. In such an embodiment, all P_Key tables of end-ports that are members of the admin partition can have a P_Key entry for the admin partition in their respective P_Key tables. In accordance with an embodiment, a data partition may be defined as any partition that is not also an admin partition.

In accordance with an embodiment, a data partition can be associated with one or more admin partitions. For example, a data partition, being defined by a P_Key value, can be associated with an admin partition that is defined by its own distinct P_Key value. Moreover, the data partition can be associated with a second admin partition defined by yet another distinct P_Key value. In accordance with an embodiment, the association of a data partition with a specific admin partition can define the maximum membership level for end-ports that are members of the specific admin partition.

As noted above, an admin partition represents a group membership which grants access rights to subnet resources. In accordance with an embodiment, any end-port member of an admin partition has access rights to any subnet resource that is associated with the same admin partition based solely on the end-port's membership in the admin partition. Thus, any end-port that is a member of an admin partition has access rights to any data partition that is associated with that same admin partition. Notably, this does not necessarily mean that the member end-port is a member of the associated data partition, but that it has access rights to the associated data partition, and therefore could be a member of the data partition.

Such a scheme obviates the need for administrators to grant end-ports access to, e.g., data partitions by manually including the data partition's P_Key in the P_Key table of the end-port. In an embodiment, when an end-port is initialized in the subnet, the master subnet manager can query a data store (e.g., an admin partition registry, as discussed below) that holds admin partition definitions (e.g., P_Keys), and relationships that define membership in the defined admin partitions and that define associations with the defined admin partitions, to determine which admin partitions the end-port is a member of. The subnet manager can then further check to see if there are any data partitions associated with the admin partitions of which the end-port is a member. If the SM finds that 1) the end-port is a member of an admin partition, and 2) that that admin partition is associated with a data partition, then the SM can automatically place the P_Key of the associated data partition in the P_Key table of the end-port, thereby automatically granting the end-port access to the data partition. Thus, the admin partition represents a simpler, more scalable solution than manual partition mapping by administrators.

FIG. 12 shows an exemplary network fabric having both admin partitions and data partitions. As shown in FIG. 12, admin partitions 1230, 1240, and 1250 have been defined within the fabric. Nodes A-E 1201-1205, are physically connected to the fabric by their respective HCAs 1211-1215. Additionally, each HCA is a member of at least one admin partition. HCA 1211 and HCA 1214 are members of admin partition 1230. HCA 1211 is also a member of admin partition 1240, along with HCAs 1212 and 1213. HCA 1213 is, additionally, a member of admin partition 1250, along with HCA 1215.

With further reference to FIG. 12, and in accordance with an embodiment, data partitions 1232, 1242, and 1252 have been defined within the fabric. Data partition 1232 is associated with admin partition 1230, data partition 1242 is associated with admin partition 1240, and data partition 1252 is associated with admin partition 1250. In accordance with an embodiment, HCA 1211 and HCA 1214 have access rights to membership in data partition 1232 based on their membership in admin partition 1230. Likewise, HCAs 1211-1213 have access rights to membership in data partition 1242 based on their membership in admin partition 1240. Moreover, HCAs 1213 and 1215 have access rights to membership in data partition 1252 based on their membership in admin partition 1250.

In accordance with an embodiment, admin partitions can also be used to determine whether a vHCA can be registered with the virtual function of a physical HCA. A vHCA describes a host channel adapter which is planned and configured for a specific virtual machine (VM), in accordance with an embodiment. A vHCA differs from a virtual function (VF) in that a vHCA migrates with a VM, while a VF stays with the physical adapter. As discussed above, however, both physical HCAs and vHCAs (and, at a lower level, the end-ports of these (v)HCAs) can be members of admin partitions. Thus, in accordance with an embodiment, admin partition membership can be used by the SM to determine whether a request from a physical HCA to register a vHCA with a virtual function of the requesting physical HCA is permissible.

FIG. 13 shows an exemplary network fabric having HCAs and vHCAs as members of admin partitions. As shown in FIG. 13, subnet 1302 is part of network fabric 1300. HCA 1310, 1324, 1332, and 1344 represent physical HCAs physically connected through their respective end-ports to network fabric 1300 in subnet 1302. HCA 1310 is associated with physical function (PF) 1312 and with virtual functions (VFs) 1314 and 1316. HCA 1324 is associated with PF 1326 and with VFs 1328 and 1329. HCA 1332 is associated with PF 1334 and with VFs 1336 and 1338. HCA 1344 is associated with PF 1346 and with VFs 1348 and 1349. Further, vHCA 1320 is depicted as registered with VF 1314, and associated with Virtual machine (VM) 1318 (i.e., VM 1318 obtains access to network fabric 1300 through vHCA 1320, and ultimately through physical HCA 1310). vHCA 1340 is registered VF 1337, and associated with VM 1338.

With continued reference to FIG. 13, as shown, HCAs 1310 and 1324, and vHCA 1320 are members of admin partition 1350. Additionally, HCA 1332 and 1344, and vHCA 1340 are members of admin partition 1360. Consequently, vHCA 1320 can be legally registered with VF 1314 or 1316 of HCA 1310, or with VF 1328 or 1329 of HCA 1324, by virtue of the fact that HCA 1310 and 1324, and vHCA 1320 are each members of admin partition 1350. Similarly, vHCA 1340 can be legally registered with VF 1336 or 1338 of HCA 1330, or with VF 1348 or 1349 of HCA 1344, by virtue of the fact that HCA 1332 and 1324, and vHCA 1340 are each members of admin partition 1360.

As noted above, the fabric-level fabric database holds information related to the fabric and fabric resources, and is managed by the fabric manager. In accordance with an embodiment, the fabric database can have “complete knowledge” of the fabric resource inventory (i.e., every resource that is a part of the network fabric is represented, at least, by a record held in the fabric database). Further, the access rights and name spaces associated with each resource in the fabric can be either stored in the fabric database, or derived from information and relationships contained in the fabric database.

For example, in accordance with an embodiment, information pertaining to admin partition membership and/or resource association with an admin partition can be stored in the fabric database. The tables holding this information and the relationships that link these tables together can be a subset of the fabric database, and can be referred to as the admin partition registry. In accordance with an embodiment, the admin partition registry is a collection of admin partition group resources. For example, an admin partition group within the admin partition registry can be a collection of HCA members (including vHCAs) and associated resources of a particular admin partition, where the group is looked up by the P_Key that defines the particular admin partition. Moreover, admin partition group members and associated resources can be looked up in the registry using keys such as GUID or vGUID for member HCAs or vHCAs, respectively, or P_Keys for associated data partitions. Relationships between the P_Key of an admin partition and the unique identifier of members or associated resources define membership or association, respectively, in the admin partition, and are maintained by the admin partition registry, and by the fabric database, at a higher level.

In accordance with an embodiment, all or part of the admin partition registry may be held as records in a cache of the SM. For instance, records of the admin partition registry that correspond to resources of a particular subnet can be duplicated in a cache in a resident memory of a subnet manager (e.g., the master subnet manager) of the particular subnet. The admin partition registry records can either be retrieved (i.e., copied) from the fabric database by the SM (e.g., when the SM boots), or be placed in the cache before it is persisted to the fabric database. The cache can be a volatile or non-volatile memory. Regardless of when the registry records are placed in the cache, synchronization can then occur between the cached copy of the admin partition registry and the copy of the admin partition registry found in a fabric-level data base.

By holding all, or a subnet-relevant part, of the admin partition registry in a high-speed cache on the SM, rather than retrieving admin partition information from a persisted state (i.e., from the fabric database) every time a query is received, the lookup of admin partition information can impose minimal overhead on the SM. This can be especially important during subnet initialization, when access rights among subnet resources are being automatically assigned.

In accordance with an embodiment, logical names or identifiers can be assigned to resources within a resource domain (by, e.g., the fabric-level or domain-level admin user). These logical names can be private to the resource domain. The fabric manager, through the fabric database, can create relationships that map unique identifiers used within the fabric (e.g., vGUIDs and P_Keys) to logical or symbolic names given to resources within the fabric.

For instance, the fabric database, in accordance with an embodiment, can store records of resources, and domain membership and/or admin partition membership of resources. Logical names can be assigned to the resources upon discovery of the resources by the fabric manger. These names can be linked to the unique identifiers of the fabric resources in the fabric database. Moreover, the fabric manager can keep track of each resource's membership in resource domains and admin partitions through a relationship in the fabric manager database. With these records and relationships, the fabric manager can allow like logical names across disparate resource domains and admin partitions. In accordance with an embodiment, the logical domain name scheme can reflect the hierarchy of the resource domain or domains that a particular domain resource is a member of. In such an embodiment, logical resource names can be unique to the highest level resource domain that the resource is a member of.

In accordance with an embodiment, the identifier of a resource in the fabric—regardless of what the identifier is—can be unique within the scope of the admin partition. Then, global uniqueness (i.e., at the fabric level) can be achieved by prefixing the resource name with the corresponding admin partition.

FIG. 14 shows an exemplary network fabric having both resource domains and admin partitions. As shown in FIG. 14, fabric manager 1402 is executing on network fabric 1400. In accordance with an embodiment, fabric manager 1402 can execute from a node (not shown) of network fabric 1400. Fabric manager 1402 is administered by fabric-level administrator 1404, and includes fabric manager database 1414. Admin partition registry 1416 is part of fabric manager database 1414, as is a logical name table 1418.

With continued reference to FIG. 14, subnet 1420 is defined within network fabric 1400. Subnet manager 1422 is associated with subnet 1420, and, in accordance with an embodiment, performs the semantic runtime operations required by subnet 1420 for operation in network fabric 1400. Setup and administrative tasks required by subnet 1420 can be performed by fabric-level administrator 1404 and fabric manager 1402.

Node 1444, 1454, 1474 and 1484 are part of subnet 1420. HCA 1446 is associated with node 1444, and includes PF 1448 and VFs 1450 and 1452. Similarly, HCA 1456 is associated with node 1454, and includes PF 1458 and VFs 1460 and 1462. HCA 1476 is associated with node 1474, and includes PF 1478 and VFs 1480 and 1482. Further, HCA 1486 is associated with node 1484, and includes PF 1488 and VFs 1490 and 1492. VM 1440 is executing on node 1444, and VM 1470 is executing on node 1474. vHCA 1442 has been planned and configured for VM 1440, is associated with VM 1440, and is registered with virtual function 1452 of HCA 1446. vHCA 1472 has been planned and configured for VM 1470, is associated with VM 1470, and is registered with virtual function 1482 of HCA 1476.

In accordance with an embodiment, HCAs 1446, 1456, 1476, and 1486 are considered domain resources, and a record of each is stored in fabric manager database 1414. The record can include an identifier, such as a GUID, which is used to identify the HCA resource in the fabric. Further, vHCAs 1442 and 1472 are also considered domain resources, and a record of each is stored in fabric manager database 1414. The record can include an identifier, such as a GUID, which is used to identify the vHCA.

With further reference to FIG. 14, and in accordance with an embodiment, resource domain 1410 and resource domain 1412 have been created within fabric manager 1402. In accordance with an embodiment, fabric-level administrator 1404 is responsible for the creation of resource domain 1410 and resource domain 1412. Additionally, domain admin 1406 is a domain-level administrator associated with resource domain 1410. Likewise, domain admin 1408 is a domain-level administrator associated with resource domain 1412. In accordance with an embodiment, fabric-level administrator 1404 can create domain admins 1406 and 1408, as admins of their respective resource domains, adhering to the hierarchical nature of resource domains.

In accordance with an embodiment, admin partition 1424 and admin partition 1426 have been defined in subnet 1420. Admin partition 1424 is associated with resource domain 1410, and admin partition 1426 is associated with resource domain 1412.

As shown in FIG. 14, vHCA 1442 and HCAs 1446 and 1456 are members of resource domain 1410. In accordance with an embodiment, because admin partition 1424 is associated with resource domain 1410, when vHCA 1442 and HCAs 1446 and 1456 are added as members of resource domain 1410, they also become members of admin partition 1424, and a relationship is created in admin partition registry 1416 between the P_Key defining admin partition 1424 and the identifiers of HCAs 1446 and 1456, and vHCA 1442. In accordance with an embodiment, this relationship defines HCAs 1446 and 1456, and vHCA 1442 as members of admin partition 1424.

Likewise, vHCA 1472 and HCAs 1476 and 1486 are members of resource domain 1412. In accordance with an embodiment, because admin partition 1426 is associated with resource domain 1410, when vHCA 1472 and HCAs 1466 and 1486 are added as members of resource domain 1412, they also become members of admin partition 1426, and a relationship is created in admin partition registry 1416 between the P_Key defining admin partition 1426 and the identifiers of HCAs 1476 and 1486, and vHCA 1472. In accordance with an embodiment, this relationship defines HCAs 1476 and 1486, and vHCA 1472 as members of admin partition 1426.

As noted above, VM 1440 (including vHCA 1442), node 1444 (including HCA 1446) and node 1454 (including HCA 1456) are members of resource domain 1410, in accordance with an embodiment. In an embodiment of the invention, fabric-level administrator 1404 is responsible for adding node 1444 and node 1454 to resource domain 1410. For example, fabric-level administrator 1404 can, through the interface of fabric manager 1402, add nodes 1444 and 1454 to resource domain 1410. Once fabric-level administrator 1404 has added nodes 1444 and 1454 to resource domain 1410, domain admin 1406 can perform administrative tasks on nodes 1444 and 1454. In keeping with the hierarchical scheme of resource domains, however, domain admin 1406 could not perform administrative tasks on nodes 1444 and 1454 before they were added to resource domain 1410 (i.e., while they were a member of the higher-level default domain (not shown). Further, in accordance with an embodiment, domain admin 1408 cannot perform administrative tasks on nodes 1444 and 1454, because nodes 1444 and 1454 are members of a parallel-level resource domain that domain admin 1408 is not associated with.

With continued reference to FIG. 14, and in accordance with an embodiment, admin partitions 1424 and 1426 have been defined within subnet 1420. In keeping with the hierarchical scheme of resource domains, in one embodiment admin partitions 1424 and 1426 were defined by fabric-level administrator 1404. In another embodiment, domain admin 1406 defined admin partition 1424, and domain admin 1408 defined admin partition 1426. In accordance with an embodiment, admin partition 1424 is associated with resource domain 1410, and admin partition 1426 is associated with resource domain 1412. As discussed above, admin partitions 1424 and 1426 represent resource domains 1410 and 1412, respectively, at the subnet level, in accordance with an embodiment. In addition to being associated with their respective resource domains, admin partitions 1424 and 1426 are associated with domain admins 1406 and 1408, respectively (i.e., the corresponding admin user of the resource domains each of the admin partitions is associated with). As noted above, this association between admin partitions and domain-level admins can ensure user-role separation in multi-tenant environments at the subnet level, in accordance with an embodiment.

Data partitions 1428 and 1430 have been defined in subnet 1420, in accordance with an embodiment. In keeping with the hierarchical scheme of resource domains, in one embodiment data partitions 1428 and 1430 were defined by fabric-level administrator 1404. In another embodiment, domain admin 1406 defined data partition 1428, and domain admin 1408 defined data partition 1430. As shown in FIG. 14, data partition 1428 is associated with admin partition 1424, and data partition 1430 is associated with admin partition 1426. Moreover, as noted above and shown in FIG. 14, HCAs 1446 and 1456 and vHCA 1442 are members of admin partition 1424. Consequently, in accordance with an embodiment, HCAs 1446 and 1456 and vHCA 1442 have access permissions to data partition 1428 because they are members of an admin partition (i.e., admin partition 1424) that data partition 1428 is associated with.

In accordance with an embodiment, when data partition 1428 is associated with admin partition 1424, a relationship between the identifier of data partition 1428 (e.g., the P_Key of data partition 1428) and the P_Key of admin partition 1424 is created in the admin partition registry 1416. This relationship defines data partition 1428 as associated with admin partition 1424. Likewise, when data partition 1430 is associated with admin partition 1426 a relationship between the identifier of data partition 1430 (e.g., the P_Key of data partition 1430) and the P_Key of admin partition 1426 is created in the admin partition registry 1416. This relationship defines data partition 1430 as associated with admin partition 1426.

In accordance with an embodiment, if a request were received from either of HCAs 1446 and 1456 or vHCA 1442 to join data partition 1428, SM 1422 could check with admin partition registry 1416, and find that HCAs 1446 and 1456 and vHCA 1442 are members of admin partition 1424, and that data partition 1428 is associated with admin partition 1424. Then, SM 1422 could allow HCAs 1446 and 1456 and vHCA 1442 to become members of data partition 1428 based on HCAs 1446 and 1456 and vHCA 1442 being members of admin partition 1424 and data partition 1428 being associated with admin partition 1424. No manual mapping from either fabric-level administrator 1404 or domain-level administrator 1406 would be necessary to allow HCAs 1446 and 1456 and vHCA 1442 to join data partition 1428.

Moreover, vHCA 1442 can be registered with either of VF 1452 or 1450 of HCA 1446, or either of VF 1462 or 1460 of HCA 1456, because HCAs 1446 and 1456 and vHCA 1442 are members of admin partition 1424 (vHCA 1442 is depicted as registered with VF 1452). Here again, SM 1422 could check with admin partition registry 1416, and find that HCAs 1446 and 1456 and vHCA 1442 are members of admin partition 1424. Upon finding that HCAs 1446 and 1456 and vHCA 1442 are members of admin partition 1424, SM 1422 could allow registration of vHCA 1442 with any of VFs 1452, 1450 1462, and 1460 without intervention from any fabric user.

Virtual Machine Fabric Profiles

As discussed above, virtual machines (VMs) can be employed in a fabric, such as an IB fabric in order to improve efficient hardware resource utilization and scalability. Yet, live migration of virtual machines (VMs), still remains an issue due to the addressing and routing schemes used in these solutions. In accordance with an embodiment, methods and systems provide for facilitating pre-defined, highly available, and physical-location independent virtual machine fabric profiles that can support addressing schemes aimed at overcoming such VM migration issues. In accordance with an embodiment, VM fabric profiles enable centralized setup and configuration administration for VMs using fabric connectivity, and support optimized VM migration for VMs based on SR-IOV. In accordance with an embodiment, a VM fabric profile represents a single, centralized repository of detailed fabric configuration information for a virtual machine. A database associated with the fabric manager (e.g., the fabric database) can persist the information that makes up a VM fabric profile.

In accordance with an embodiment, a VM fabric profile can be identified in a network fabric, such as an IB fabric, through a virtual machine identifier (VM-id). In one embodiment, the VM-id is a unique 128-bit number that is a universally unique identifier (UUID), that can be unique across the entire fabric. However, uniqueness of the VM-id is only necessary across differently administered VM manager domains (e.g., a VM-id can be unique within an admin partition). Therefore, in other embodiments, the VM-id can be some other appropriate type of ID that is at least unique across such domains. In accordance with an embodiment, all management entities, at either the fabric or the subnet level, look up information about a VM fabric profile by referencing the VM-id of the profile.

FIG. 15 shows an exemplary database structure for storing VM fabric profile information. FIG. 15 depicts several tables in a traditional relational database design. However, any suitable data structure can be used to store VM fabric profile data (e.g., a flat-file table, or a delimited structure, etc.). In FIG. 15, an asterisk (*) denotes a key value. FIG. 15 depicts VM fabric profile data as being part of a larger fabric database 1500, but in other embodiments, VM profile data may be contained in its own database, or may be a separate database with access to fabric database 1500.

As shown in FIG. 15, the contents of a VM fabric profile may include, but are not limited to: a virtual machine identifier (VM-id) 1502 used as a lookup key; a logical name 1504 for ease of use and improved quality in administration of the fabric; a profile type 1506 used to distinguish between, e.g., a VM fabric profile and other profiles that have been defined for the fabric; a profile ID 1508—a unique id within the set of all profiles defined for the fabric; and a content update enumerator (CUE) 1510, which can be a sequence number for a profile where the highest sequence represents the most recent update. As shown in FIG. 15, this VM fabric profile content can be stored in a VM profile table 1512, where the VM-id acts as a unique key for identifying each VM fabric profile.

As discussed above, virtual HCAs (vHCAs) may be used in conjunction with the virtual functions of a physical HCA to provide network access to VMs. In accordance with an embodiment, each VM fabric profile is also associated with at least one vHCA. A vHCA can be planned and configured for a specific VM, and this configuration can also be included in and stored with the fabric profile of the VM for which the vHCA is configured. The configured vHCA can then migrate with the virtual machine—in contrast to virtual functions, which can be defined by, and can stay with, the physical HCA. With further reference to FIG. 15, a vHCA can be represented in the fabric manager database as a unique combination of a VM-id 1502 and a vHCA Instance ID 1514. Moreover, this combination can be stored in a vHCA table related to the VM Profile table 1512 through the VM-id key 1502.

Like a physical HCA, a vHCA can have a plurality of (virtual) ports. In accordance with an embodiment, these virtual ports can act as end-ports in the network environment, just as physical ports do. As an example, all end-ports, including vHCA ports, can be assigned a GUID (e.g., a 64-bit GUID as used in an IB network). This GUID can be used to request a LID destination address from the routing tables of a SM. In accordance with an embodiment, a virtual GUID (vGUID) can represent the current fabric address of each vHCA port. In one embodiment, vGUIDs can be assigned to the vHCA ports from a list of GUIDs allocated to, and stored with, the VM fabric profile, as discussed above. vGUIDs can be assigned to a fabric profile from a dedicated pool of GUIDs owned and controlled by the fabric manager in accordance with fabric manager GUID policy. For instance, a free and fabric-wide unique vGUID can be allocated to a vHCA configured for a VM when the fabric profile is created in the fabric manager.

With continued reference to FIG. 15, and in accordance with an embodiment, a vHCA port can be represented in the fabric manager database as the unique combination of a vHCA Instance ID 1514, and a vGUID 1522. A vHCA configuration can also include a vHCA port number 1520. This configuration can be stored in the vHCA port table 1518, which can be related the vHCA table through the vHCA Instance ID* 1514 key, and ultimately to the VM profile table 1512 through the VM-id key 1502.

In accordance with an embodiment, a vHCA can be a member of both data partitions and admin partitions. Partition membership of a vHCA can be represented in a VM fabric profile by relationships in the fabric database linking the vHCA record to partitions (both admin and data partitions) that the vHCA is a member off. In one embodiment, for example, the vGUID key 1522 can be related to tables (not shown) containing data and admin partitions P_Keys that have been defined in the network fabric. In an embodiment, the vGUID key is linked, through a relationship, to the admin partition registry (discussed above). In an embodiment, there is alternatively, or also, a relationship linking the admin partition registry to a vHCA Instance ID 1514. These relationships allow fabric components to identify which data and admin partitions the vHCA is a member of.

FIG. 15 has been provided for exemplary purposes only, and one skilled in the art will appreciate that there are numerous ways to design and manage the storage of the data that make up a VM fabric profile. Further, the foregoing list of VM fabric profile contents is meant to be exemplary, not limiting, and other embodiments of virtual machine fabric profiles may include more, less, or other contents. In accordance with an embodiment, the database components depicted in FIG. 15 can be a part of a much larger fabric manager database that holds other relevant information about the fabric and can be interrelated with other tables to enhance the functionality of the fabric manager and other fabric components.

In one embodiment, a user interacts with virtual machine fabric profiles through an interface of the fabric manager. For instance, a user may create, edit, and delete VM fabric profiles through the fabric manager. In accordance with an embodiment, some of the fabric profile information is supplied by a user creating or editing the VM fabric profile (e.g., the logical name of the VM fabric profile), while other of the information is generated or supplied by the fabric manager or the local SM of the subnet in which the fabric manager is being created (e.g., the VM-id, the vHCA instance ID, or the vGUID).

In accordance with an embodiment, the creation of the virtual machine fabric profile can take place in a management context that represents administrative privileges of the fabric resources the VM fabric profile is associated with. For example, a domain admin creates a VM fabric profile for use by nodes having HCAs that are a member of the same resource domain(s) (and the same admin partition(s)) as the vHCAs being configured for the VM fabric profile. The created VM fabric profile is considered a (logical) resource, and a member of the resource domain in which it is created. Thus, by virtue of being a member of the same admin partition, the vHCA of the VM fabric profile has permission to be registered with any of the VF's of the HCAs that are also members of the resource domain, thereby easing administrative overhead.

In accordance with an embodiment, a fabric-level or domain-level administrator user can use a component of the fabric manager termed the “Virtual Machine Manager” (VMM) to set up and configure VM fabric profiles. VMM can use a fabric REST API in the creation of a VM fabric profile. A user can access VMM, for example, through a GUI of the fabric manager. In accordance with an embodiment, the administrative user can supply certain parameters related to the VM fabric profile (such as logical name, profile type, and the number of vHCAs that will be associated with the profile), and other parameters can be automatically generated and assigned by the VMM (such as VM-id, and vGUIDs and vHCA instance IDs of each vHCA associated with the profile). Other CRUD actions, such as updating and deleting VM fabric profiles can also be available to the administrator user through the fabric manager, and VMM, specifically.

In accordance with an embodiment, once all of the parameters necessary to build a VM fabric profile have been supplied via the VMM, the fabric manager can create an instance of the VM fabric profile object having the attributes specified by the administrator user and VMM, and persist the VM fabric profile object to the fabric level database.

In accordance with an embodiment, in an operational network fabric, a VM fabric profile can be held as one or multiple records in a cache of a SM. The VM fabric profile can either be retrieved (i.e., copied) from the fabric database by the SM (e.g., when the SM boots), or be placed in the cache before it is persisted to the fabric database. The cache can be a volatile or non-volatile memory. The VM-id can be used as a key for querying the cache to retrieve attributes of a specific VM fabric profile.

By holding the VM fabric profiles in a high-speed cache on the SM rather than retrieving them from a persisted state (i.e., from the fabric database) every time a query is received, the lookup of VM fabric profile attributes can impose minimal overhead on the SM. This is especially important during VM and host boot-up, when fabric profile data will be needed to establish which HCAs VMs can and will be paired with.

FIG. 16 is a flow chart for making a VM fabric profile available to subnet resources.

At step 1610, a VM fabric profile including setup parameters and configuration of the VM is defined.

At step 1620, the VM fabric profile is stored in a fabric-level database.

At step 1630, the VM fabric profile is made available through a high-speed memory cache on the subnet manager.

At step 1640, VM fabric profile data is returned from the subnet manger based on VM-id lookup requests directed to the high-speed memory cache.

Virtual Machine ID and Migration Manager (VIMM)

In accordance with an embodiment, and as discussed above, the subnet manager and fabric-connected HCAs play an integral role in facilitating the above-described advances and efficiencies, such as admin-partition-to-data-partition mapping, and the management and lookup of VM information through virtual machine fabric profiles. These advances allow for more efficient fabric resource utilization, including more efficient use of both administrative resources and hardware resources. To date, however, the functionality required by SMs in order to take advantage of the technological advances described herein is not defined in the IB specification for SMs and/or HCAs. Moreover, network fabrics controlled by currently available SM software (e.g., OpenSM, or Oracle's® NM2 SM) do not support the above-disclosed technology. Therefore, new SM and HCA configurations are needed in order to take advantage of the disclosed advances, while still remaining compatible with legacy hardware and software, so that gradual implementation of the above-disclosed technological advances can be achieved.

As discussed above, SMs, through the SM interface, exchange control packets, which are referred to as subnet management packets (SMPs), with subnet management agents (SMAs). The subnet management agents reside on every IB subnet device (e.g., each HCA can have a resident SMA). By using SMPs, the subnet manager is able to discover the fabric, configure end-nodes and switches, and receive notifications from SMAs. In accordance with an embodiment, SMs and HCAs can be configured to take advantage of the above disclosed technological advances by including a proprietary extension of both the SM and the SMA. A virtual machine ID and migration manager (VIMM) can extend the functionality of SMs. Likewise, a virtual machine ID and migration manager agent (VIMMA) can extend the functionality of SMAs, and in turn, the functionality of HCAs (and vHCAs).

In accordance with an embodiment, VIMM can receive requests for end-port membership in data partitions and perform the appropriate look-ups in order to check that the requesting end-port is a member of an admin partition that is associated with the data partition for which membership has been requested (as described above). Moreover, VIMM can manage requests from a host to start a VM on the host, or migrate a VM to the host, where the VM is defined in a VM fabric profile, and where the vHCA of the host can be registered with the VF of an SR-IOV enabled HCA to give the VM network access (as described above).

VIMMA, in accordance with an embodiment, can reside on SR-IOV enabled HCAs and work as an agent of VIMM—in much the same way as the SM and SMA work together—by acting as a proxy for requests from hyper-privileged control software on the host (e.g., a hypervisor implemented in Dom0 for Linux, or a Control Domain such as an LDOM in Solaris) to VIMM. Communication between the hyper-privileged control software and VIMMA can be enabled through a control application programming interface (API).

In one embodiment the VIMMA extension component can be located in the embedded processor of the HCA device and implemented as part of an updateable firmware of the device, thereby allowing updates to the VIMMA extension components. Additionally, the control API can be implemented as a user-space shared library on top of a physical function (PF) kernel driver of the HCA device. The shared library can be installed as part of a generic host stack that can also respond if invoked from a privileged domain having access to the PF driver of the HCA. This means that a VM, via a virtual driver will not be able to make function calls to the control API, communicate with VIMMA in the HCA, or access other types of HCAs.

FIG. 17 shows an exemplary HCA including the control API, in accordance with an embodiment. HCA 1700 includes PF 1720, VF 1 1730, VF 2 1740, and VF N 1750. Additionally, HCA 1700 includes control circuit 1724. Control circuit 1724 can include a processor and a memory (not shown). The VIMMA module 1726 executes on control circuit 1724. Hypervisor 1710 is an example of hyper-privileged control software (implemented, e.g., in Dom0 or a Control Domain). Hypervisor 1710 can invoke control API 1722, and has access to functions exposed by control API 1722.

Virtual Machine Incarnation Numbers

As discussed above, fabric and administrative overhead can be reduced through the use of innovations such as admin partitions, admin-partition-to-data-partition mapping, VM fabric profiles, and VIMM/VIMMA extensions to the SM and SMA (respectively). For instance, hyper-privileged software on a host can request that a VM be started on, or migrated to, the host through a call to a control API, which can be exposed through the physical function (PF) driver of the physical HCA. The API can expose functionality of the VIMMA extension module to the SMA agent. VIMMA can receive and proxy the request to VIMM—an extension of the SM that makes the SM compatible with VM fabric profiles and the other above-mentioned advances. VIMM can receive the request, which, at the VIMM level, can be a request to register a vHCA of a VM fabric profile with a virtual function (VF) of the requesting HCA. VIMM can then check that the HCA is a member of at least one admin partition associated with the requested fabric profile (i.e., that it is legal for the HCA to request the specified VM Fabric Profile from the VIMM, and for the VIMM to send the vHCA configuration to be registered with a VF of the requesting HCA). If, after checking, VIMM determines that it is legal to register the vHCA with the VF of the requesting HCA, VIMM can send the vHCA configuration information to be registered to the requesting HCA.

In accordance with an embodiment, this registration process is an initial step in dynamically starting a VM on a host, or migrating a VM to a different host. After the vHCA is registered with the VF of the requesting physical HCA, the vHCA can be “brought up”—that is, it can be configured to appear as a live HCA on the subnet, having all the attributes a physical HCA has. Thereafter, the VM associated with the vHCA can communicate with the network via the vHCA. As mentioned before, such dynamic behavior is highly desirable, and allows for on-demand, live migration of virtual machines with little or no administrative effort, in accordance with an embodiment.

In order to provide for an orderly migration of a VM, a deregistration of a vHCA can be performed before a new registration of that vHCA can take place, in accordance with an embodiment. This is necessary because, from the perspective of high-level management components (such as VIMM, VMM, and other network components), the vHCA is already “running” at the previous VM host location, and it is problematic to have a same vHCA instance (with a same vGUID(s)) active at two different host locations in the subnet.

In accordance with an embodiment, a de-registration can be initiated by hyper-privileged control software executing on the host (e.g., host hypervisor software) through the control API. VIMMA can receive the de-registration request and can immediately bring down the ports/links of the vHCA, causing data-plane traffic to immediately stop flowing. In the background VIMMA can forward the de-registration request to VIMM, so that VIMM can update the appropriate records in a cache of active registrations held by VIMM. Once the de-registration is completed from the host's perspective (i.e., after the de-registration call to the control API has returned), the hyper-privileged software is free to issue a new registration request. Such a new request can either be for the same VM, or a different VM.

Notably, a de-registration request operates to take the (v)links of the previously registered vHCA down. These links will remain down until the VF is re-registered with a vHCA. Thus, the previously registered VF link in “down state” can act as an indicator to VIMM that the earlier registered vHCA can be registered again on some other HCA/host, in accordance with an embodiment.

In an orderly migration of a VM, there is no need for a forceful shutdown of a vHCA by management components. But there are scenarios in which an orderly migration may not be possible. For instance, in the event of a dysfunctional (or “rogue”) hypervisor that will not make a de-registration call to the control API, but where higher-level management components have determined that a migration of the VM running on the rogue hypervisor is optimal, VIMM would need to force a shutdown of the VM on the host having the rogue hypervisor. Similarly, in a scenario where VIMM has lost communication with the VM, but where the physical HCA and the ports/links of the registered vHCA are still active, VIMM would need to force a shutdown of the VM on the host having the rogue hypervisor in order to migrate the VM to a different host. These types of scenarios, requiring a forceful shutdown of a vHCA and corresponding VM, can be referred to herein as “split-brain” scenarios.

Regardless of the details of a split-brain scenario, forceful de-registration of a vHCA associated with a VM that needs to be migrated can be handled through the use of VM incarnation numbers, in accordance with an embodiment. VM incarnation numbers can indicate which instantiation of a VM is the newest instantiation as seen from the VIMM extension module's point of view (i.e., the last started “incarnation” of a VM as identified by a particular VM-id). For instance, in a scenario where high-level fabric management has decided that a VM should be migrated, VIMM can evaluate a VM incarnation number sent with the request to start a VM on a host, and determine that the VM incarnation number value allows for the VM to be started on the requesting host. If the value of the received VM incarnation number indicates the legality of the requested registration, then VIMM can force a shutdown of the currently running vHCA associated with the VM to be migrated, and start registration of the vHCA with a VF of the requesting HCA.

As discussed herein, in order to indicate a legal request for registration, a VM incarnation number accompanying a registration request must be higher than the VM incarnation number associated with the active instance of the VM, in accordance with an embodiment. Therefore, a VM incarnation number value of two (2) received with a request to register a vHCA of a currently-active VM will be considered a legal if, upon evaluating the received VM incarnation number value with the VM incarnation number value associated with the currently-active VM, it is determined that the VM incarnation number value associated with the currently-active VM is less than two (2). In order to achieve higher values, VM incarnation numbers can be incremented. A person having skill in the art will appreciate that legality of a request for registration could, just as easily, be indicated by a VM incarnation number having a lower value than one associated with a currently-active VM without any substantive difference in the outcome, and that legality indicated by a higher VM incarnation number is merely a design preference.

In accordance with an embodiment, a physical HCA can store, as an attribute, a VM incarnation number for each VF of the HCA. This attribute can be modified by hyper-privileged software (e.g., a hypervisor) executing on the host through the control API. Each VM incarnation number attribute (corresponding to each VF) can have a default value. The hyper-privileged software, through the control API, can increment the value of the VM incarnation number if needed. For example, in the case where a higher VM incarnation number is needed in order to start the migration process, the hyper privileged software can increment the VM incarnation number through functionality exposed by the control API and send a new request including the incremented VM incarnation number.

As discussed above, the SM can maintain a cache of active VM registrations on the subnet, in accordance with an embodiment. This cache can include the VM incarnation number of each active VM on the subnet. Recall, that a VM-id is a unique identifier of each VM defined in the network, and is stored as a part of each VM fabric profile. Each VM incarnation number can be related to the VM-id number of an active VM in the cache. The VM-id (as the central identifier of each active VM in the cache), can be used as a lookup key for each active VM in the subnet. Using the VM-id, the SM can retrieve all of the information in the cache about a given active VM. The SM can, in accordance with an embodiment, initially build the cache using information gathered on a heavy sweep of the network. The cache can be maintained through subsequent sweeps, or through trap messages received from HCAs on the subnet.

FIG. 18 shows an exemplary HCA including configurable attributes, in accordance with an embodiment. HCA 1800 includes PF 1820, VF 1 1830, VF 2 1840, and VF N 1850. Additionally, HCA 1800 includes control circuit 1824. Control circuit 1824 can include a processor (not shown) and a memory 1828. The VIMMA module 1826 executes as an extension to the subnet management agent (SMA, not shown) on control circuit 1824. Memory 1828 can hold configurable attributes 1829 (e.g., a VM incarnation number attribute of a corresponding VF). Each VM incarnation number attribute can have a default value. Memory 1828 can be a nonvolatile memory, a volatile random access memory, or can include both volatile and nonvolatile memory.

Hypervisor 1810 is an example of hyper-privileged control software (implemented, e.g., in Dom0 or a Control Domain of the host). Hypervisor 1810 can invoke control API 1822, and has access to, and can call, functions exposed by control API 1822. In accordance with an embodiment, hypervisor 1810 (or other hyper-privileged control software) can set configurable attributes 1829 through functionality exposed by control API 1822. For example, Hypervisor can, if needed, increment the value of a VM incarnation number of a corresponding VF (e.g., VF 1, 1830).

With continued reference to FIG. 18, and in accordance with an embodiment, configurable attributes 1829 can be exposed in a read-only configuration to VIMM enabled subnet manager 1860. This allows VIMM enabled SM 1860 to discover, for example, the value of a VM incarnation number attribute during a heavy sweep of the network (or, e.g., by receiving a trap message from VIMMA 1826). SM 1860 can then record the value of the discovered VM incarnation number attribute in the active VM registration cache 1862, along with the corresponding VM-id of the active VM associated with the vHCA registered with the VF whose VM incarnation number attribute was discovered. SM 1860 can ensure that a relationship between the recorded VM incarnation number attribute value and the recorded VM-id of the corresponding active VM is created and maintained in the cache, so that the SM 1860 can always know the value of the VM incarnation number when referencing the VM-id of the active VM.

Although FIG. 18 shows SM 1860 as having “read-only” access to the configurable attributes, in other embodiments, VIMM enabled SM 1860 can read and write at least some of the configurable attributes 1829. Further, as will be appreciated by a person having skill in the art, although FIG. 18 shows the active VM registration cache 1862 as residing on the VIMM enabled subnet manger 1860, the active VM registration cache 1862 can reside anywhere, so long as VM 1860 can communicate with active VM registration cache 1862 and retrieve information from active VM registration cache 1862. Active VM registration cache 1862 can comprise high-speed volatile memory, non-volatile memory, both volatile and non-volatile memory, or any suitable memory type.

In accordance with an embodiment, the SM can perform an initial sweep of the subnet, and can discover any active VM instances running on hosts within the subnet. During the sweep, for a given active virtual machine, the SM can discover attributes of the VM that are stored in the memory of the HCA and exposed by the HCA to the SM. For example, the SM can discover the vHCA instance ID of a vHCA registered with a VF of the HCA, and the VM incarnation number of the virtual machine associated with the vHCA registered with a VF of the HCA—both of which can be exposed, for example, as attributes of the HCA. The SM can record this information in an active VM registration cache. The active VM registration cache can maintain relationships between the vHCA, the VM incarnation number, and the VM-id associated with the active VM. In accordance with an embodiment, the SM can discover, and the active VM registration cache can hold, other attributes discovered by the SM upon a sweep of the network, and is not limited to the attributes discussed herein.

In one embodiment, the data structure of the active data cache can reflect all or part of the database structure for storing VM fabric profile information, (see FIG. 15 for an exemplary structure with relationships). Further, the active VM registration cache can be the same cache as the SM high-speed data cache for holding VM fabric profile information discussed above, or it can be a different cache.

As mentioned above, a split-brain scenario can take place, where the high-level VIMM/VIMMA management components are unable to establish needed communication with a VM on the subnet, but where the vHCA still appears to the SM to be operational (i.e., the vHCA vPorts will appear to be online, have visible (v)GUIDs, and be linked to a (v)switch). In accordance with an embodiment, as long as the vHCA of an active VM appears operational, another registration of the vHCA with a different VF of a different HCA is not legal. Yet, the high-level management components of the subnet have identified a need for the active VM to migrate.

In such a scenario, a host requesting that a VM be migrated to the requesting host can include a VM incarnation number with the request. The value of the VM incarnation number can be evaluated by VIMM once received, and if the VM incarnation number is high enough, VIMM can force the shutdown of the vHCA on the active host, and allow registration of the vHCA on the requesting host.

FIG. 19 shows subnet hosts with VM incarnation numbers as attributes of HCAs, in accordance with an embodiment. Host A 1920 includes hypervisor 1922 and HCA 1924. VIMMA extension module 1932 executes on HCA 1924. VM instance 1926 is active on host 1920. vHCA 1928 of VM instance 1926 is registered with VF 1930. VM Incarnation number 1934 is associated with VM instance 1926 through VF 1930 and vHCA 1928. VM Incarnation number 1934 is exposed to SM 1910 as an attribute of HCA 1924.

Subnet manager 1910 includes VIMM extension module 1912 and active VM registration cache 1914.

Host B 1940 includes hypervisor 1942 and HCA 1944. HCA 1944 includes VIMMA extension module 1952, VF 1950, and VM incarnation number 1954.

With continued reference to FIG. 19, hypervisor 1922 can control VM instance 1926, and VM instance 1926 can communicate with the network, including SM 1910, through vHCA 1928, and ultimately through HCA 1924. As noted above, a split brain scenario can occur if high-level management components, such as the virtual machine manager (“VMM”—not shown), are unable to communicate with VM instance 1926, but if VIMM 1912 still sees vHCA 1928 as an operational HCA. In such a case, hypervisor 1942 (executing on host B 1940) may believe VM instance 1926 has become inactive, and can request (through the control API and using VIMMA 1952 as a proxy) registration of vHCA 1928 with VF 1950 of physical HCA 1944. However, because vHCA is still operational from the perspective of SM 1910 and VIMM 1912, a second registration of vHCA 1928 is not legal, and VIMM 1912 can reply to the registration request with an error message.

In sending the request for registration of vHCA 1928 with VF 1950, VIMMA module 1952 can include VM incarnation number 1954 with the request. As discussed above, VM incarnation number 1954 may be a default incarnation number, or a low incarnation number. When VIMM module 1912 receives VM incarnation number 1954 with the request, VIMM 1912 can evaluate VM incarnation number 1954 comparing it to the VM incarnation number 1934, which is held in the active VM registration cache 1914, and which is related to the VM-id that represents VM instance 1926. When VIMM 1912 determines that the value of VM incarnation number 1954 is less than or equal to VM incarnation number 1934, VIMM 1912 can include (along with the error message) a notification to VIMMA 1952 to request registration of vHCA 1928 with a higher VM incarnation number. VIMMA can forward this error message and notification to the hypervisor 1942.

Upon receipt of the error message, and the notification that a higher VM incarnation number is needed, the hypervisor 1942 can increment the value of VM incarnation number 1954 through functionality exposed by the control API. Then, hypervisor 1942 (again, through functionality exposed by the control API to hypervisor 1942, and with VIMMA 1952 as a proxy) can resend the request to VIMM 1912 via SM 1910. When VIMM module 1912 receives the incremented value of VM incarnation number 1954 along with the renewed request to register vHCA 1928 with VF 1950, VIMM 1912 can again evaluate VM incarnation number 1954. If the incremented value of VM incarnation number 1954 is now greater than the value of VM incarnation number 1934, VIMM 1912 can recognize that the registration requested by VIMMA 1952 is valid because the value of the VM incarnation number included with the request is higher than the VM incarnation number related to the VM-id that represents VM instance 1926 in the active VM registration cache 1914.

With regard to an active VM, once a request to register the vHCA of the active VM is received, and that request includes a higher VM incarnation number than the VM incarnation number currently associated with the active VM, VIMM can recognize that the request to register the active vHCA is legal, and can forcefully bring the vHCA to a down state and begin a new registration of the vHCA on the VF of the requesting HCA. That is, the vPorts of the registered vHCA (e.g., vHCA 1928 registered with VF 1930) can be brought to a down state, and deregistration of the vHCA can be initiated, including deletion of the vHCA configuration from the VF/HCA with which it is currently registered. The configuration can then be provided to the requesting VF/HCA.

FIG. 20 is a flow chart of a process of forced deregistration of a vHCA from a VF.

At step 2010, a first VM incarnation number is recorded in an active VM registration cache, where the first VM incarnation number is associated with an active VM having a vHCA registered with a first VF of a first HCA.

At step 2020, a request to register the vHCA with a second virtual function of a second HCA is received, where the request includes a second VM incarnation number.

At step 2030, the second VM incarnation number is evaluated with respect to the first VM incarnation number to determine that the request is legal.

At step 2040, the vHCA is forcefully deregistered from the first VF of the first HCA.

FIG. 21 is a flow chart for initiating a forced migration of a virtual machine from one host to another.

At step 2110, a subnet manager is provided, where the subnet manager is physically connected to a network fabric.

At step 2120, an active virtual machine registration cache is provided, where the active VM registration cache is accessible to the SM via the network fabric.

At step 2130, the subnet manager records, in the active virtual machine registration cache, a first virtual machine incarnation number, where the first virtual machine incarnation number is associated with an active virtual machine, and where a virtual host channel adapter of the active virtual machine is registered with a first virtual function of a first physical host channel adapter.

At step 2140, the subnet manager receives a request to register the virtual host channel adapter of the active virtual machine with a second virtual function of a second physical host channel adapter, where the request includes a second virtual machine incarnation number.

At step 2150, the subnet manager evalutes the second virtual machine incarnation number with respect to the first virtual machine incarnation number.

At step 2160, the subnet manager determines, based on the evaluation, that the request to register the virtual host channel adapter of the active virtual machine with the second virtual function of the second physical host channel adapter is legal.

At step 2170, the subnet manager forces a virtual port of the virtual host channel adapter into a down state.

At step 2180, the subnet manager sends a configuration of the virtual host channel adapter to the second host channel adapter in response to the request to register the virtual host channel adapter.

Many features of the present invention can be performed in, using, or with the assistance of hardware, software, firmware, or combinations thereof. Consequently, features of the present invention may be implemented using a processing system (e.g., including one or more processors).

Features of the present invention can be implemented in, using, or with the assistance of a computer program product which is a storage medium (media) or computer readable medium (media) having instructions stored thereon/in which can be used to program a processing system to perform any of the features presented herein. The storage medium can include, but is not limited to, any type of disk including floppy disks, optical discs, DVD, CD-ROMs, microdrive, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of media or device suitable for storing instructions and/or data.

Stored on any one of the machine readable medium (media), features of the present invention can be incorporated in software and/or firmware for controlling the hardware of a processing system, and for enabling a processing system to interact with other mechanism utilizing the results of the present invention. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems and execution environments/containers.

Features of the invention may also be implemented in hardware using, for example, hardware components such as application specific integrated circuits (ASICs). Implementation of the hardware state machine so as to perform the functions described herein will be apparent to persons skilled in the relevant art.

Additionally, the present invention may be conveniently implemented using one or more conventional general purpose or specialized digital computer, computing device, machine, or microprocessor, including one or more processors, memory and/or computer readable storage media programmed according to the teachings of the present disclosure. Appropriate software coding can readily be prepared by skilled programmers based on the teachings of the present disclosure, as will be apparent to those skilled in the software art.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention.

The present invention has been described above with the aid of functional building blocks illustrating the performance of specified functions and relationships thereof. The boundaries of these functional building blocks have often been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Any such alternate boundaries are thus within the scope and spirit of the invention.

The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. Many modifications and variations will be apparent to the practitioner skilled in the art. The modifications and variations include any relevant combination of the disclosed features. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. 

What is claimed is:
 1. A method for initiating a migration of a virtual host channel adapter comprising: providing a subnet manger, the subnet manager configured to be physically connected to a network fabric; providing an active virtual machine (VM) registration cache, wherein the active VM registration cache is accessible to the subnet manager; recording, by the subnet manager in the active virtual machine registration cache, a first virtual machine incarnation number, wherein the first virtual machine incarnation number is associated with an active virtual machine, and wherein a virtual host channel adapter of the active virtual machine is registered with a first virtual function of a first physical host channel adapter; receiving, by the subnet manager, a request to register the virtual host channel adapter of the active virtual machine with a second virtual function of a second physical host channel adapter, wherein the request includes a second virtual machine incarnation number; evaluating, by the subnet manager, the second virtual machine incarnation number with respect to the first virtual machine incarnation number; determining, by the subnet manager, and based on the evaluation, that the request to register the virtual host channel adapter of the active virtual machine with the second virtual function of the second physical host channel adapter is legal; forcing, by the subnet manager, a virtual port of the virtual host channel adapter into a down state; and sending, by the subnet manager, a configuration of the virtual host channel adapter to the second host channel adapter in response to the request to register the virtual host channel adapter.
 2. The method of claim 1, wherein the evaluation includes a comparison of the first VM incarnation number and the second VM incarnation number.
 3. The method of claim 2, wherein the request to register the vHCA of the active VM with the second virtual function of the second HCA is determined to be legal when the second VM incarnation number is evaluated as greater than the first VM incarnation number.
 4. The method of claim 1, wherein the first virtual machine incarnation number is exposed to the subnet manager as a read-only attribute of the first host channel adapter; and wherein the second virtual machine incarnation number is exposed to the subnet manager as a read-only attribute of the second host channel adapter.
 5. The method of claim 4, further comprising discovering, by the subnet manager, the first incarnation number through the exposed read-only attribute.
 6. The method of claim 1, further comprising: deregistering the virtual host channel adapter from the first virtual function, including deleting the configuration of the virtual host channel adapter from the first physical host channel adapter.
 7. The method of claim 1, further comprising: receiving, by the second physical host channel adapter, the configuration of the virtual host channel adapter; registering the configuration with the second virtual function; and making the virtual host channel adapter operative on the network fabric.
 8. A system for initiating a migration of a virtual host channel adapter, the system comprising: an active virtual machine (VM) registration cache; and a subnet manager executing on a processor, and physically connected to a network fabric, wherein the active virtual machine registration cache is accessible to the subnet manager, and wherein the subnet manager operates to: record, in the active virtual machine registration cache, a first virtual machine incarnation number, wherein the first virtual machine incarnation number is associated with an active virtual machine, and wherein a virtual host channel adapter of the active virtual machine is registered with a first virtual function of a first physical host channel adapter; receive request to register the virtual host channel adapter of the active virtual machine with a second virtual function of a second physical host channel adapter, wherein the request includes a second virtual machine incarnation number; evaluate the second virtual machine incarnation number with respect to the first virtual machine incarnation number; determine, based on the evaluation, that the request to register the virtual host channel adapter of the active virtual machine with the second virtual function of the second physical host channel adapter is legal; force a virtual port of the virtual host channel adapter into a down state; and send a configuration of the virtual host channel adapter to the second host channel adapter in response to the request to register the virtual host channel adapter.
 9. The system of claim 8, wherein the evaluation includes a comparison of the first VM incarnation number and the second VM incarnation number.
 10. The system of claim 9, wherein the request to register the vHCA of the active VM with the second virtual function of the second HCA is determined to be legal when the second VM incarnation number is evaluated as greater than the first VM incarnation number.
 11. The system of claim 8, wherein the first virtual machine incarnation number is exposed to the subnet manager as a read-only attribute of the first host channel adapter; and wherein the second virtual machine incarnation number is exposed to the subnet manager as a read-only attribute of the second host channel adapter.
 12. The system of claim 11, wherein the subnet manager operates to discover the first incarnation number through the exposed read-only attribute.
 13. The system of claim 8, wherein after the virtual port of the virtual host channel adapter is forced into a down state, the virtual host channel adapter is deregistered from the first virtual function, including deleting the configuration of the virtual host channel adapter from the first physical host channel adapter.
 14. The system of claim 8, wherein the second physical host channel adapter receives the configuration of the virtual host channel adapter; wherein the configuration is registered with the second virtual function; and wherein the virtual host channel adapter is made operative on the network fabric as a virtual host channel adapter of the second physical host channel adapter.
 15. A non-transitory computer readable storage medium, including instructions stored thereon for initiating a migration of a virtual host channel adapter, which when read and executed by one or more computers cause the one or more computers to perform steps comprising: providing a subnet manger, the subnet manager configured to be physically connected to a network fabric; providing an active virtual machine (VM) registration cache, wherein the active VM registration cache is accessible to the subnet manager; recording, by the subnet manager in the active virtual machine registration cache, a first virtual machine incarnation number, wherein the first virtual machine incarnation number is associated with an active virtual machine, and wherein a virtual host channel adapter of the active virtual machine is registered with a first virtual function of a first physical host channel adapter; receiving, by the subnet manager, a request to register the virtual host channel adapter of the active virtual machine with a second virtual function of a second physical host channel adapter, wherein the request includes a second virtual machine incarnation number; evaluating, by the subnet manager, the second virtual machine incarnation number with respect to the first virtual machine incarnation number; determining, by the subnet manager, and based on the evaluation, that the request to register the virtual host channel adapter of the active virtual machine with the second virtual function of the second physical host channel adapter is legal; forcing, by the subnet manager, a virtual port of the virtual host channel adapter into a down state; and sending, by the subnet manager, a configuration of the virtual host channel adapter to the second host channel adapter in response to the request to register the virtual host channel adapter.
 16. The non-transitory computer readable storage medium of claim 15, wherein the evaluation includes a comparison of the first VM incarnation number and the second VM incarnation number.
 17. The non-transitory computer readable storage medium of claim 16, wherein the request to register the vHCA of the active VM with the second virtual function of the second HCA is determined to be legal when the second VM incarnation number is evaluated as greater than the first VM incarnation number.
 18. The non-transitory computer readable storage medium of claim 15, wherein the first virtual machine incarnation number is exposed to the subnet manager as a read-only attribute of the first host channel adapter; and wherein the second virtual machine incarnation number is exposed to the subnet manager as a read-only attribute of the second host channel adapter.
 19. The non-transitory computer readable storage medium of claim 15, the steps further comprising: deregistering the virtual host channel adapter from the first virtual function, including deleting the configuration of the virtual host channel adapter from the first physical host channel adapter.
 20. The non-transitory computer readable storage medium of claim 15, the steps further comprising: receiving, by the second physical host channel adapter, the configuration of the virtual host channel adapter; registering the configuration with the second virtual function; and making the virtual host channel adapter operative on the network fabric. 